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Abstract Purpose An artificial placenta (AP) utilizing extracorporeal life support (ECLS) could avoid the harm of mechanical ventilation (MV) while allowing the lungs to develop. Methods AP lambs (n = 5) were delivered at 118 days gestational age (GA; term = 145 days) and placed on venovenous ECLS (VV-ECLS) with jugular drainage and umbilical vein reinfusion. Lungs remained fluid-filled. After 10 days, lambs were ventilated. MV control lambs were delivered at 118 ("early MV"; n = 5) or 128 days ("late MV"; n = 5), and ventilated. Compliance and oxygenation index (OI) were calculated. After sacrifice, lungs were procured and H&E-stained slides scored for lung injury. Slides were also immunostained for PDGFR-α and α-actin; alveolar development was quantified by the area fraction of alveolar septal tips staining double-positive for both markers. Results Compliance of AP lambs was 2.79 ± 0.81 C dyn compared to 0.83 ± 0.19 and 3.04 ± 0.99 for early and late MV, respectively. OI in AP lambs was lower than early MV lambs (6.20 ± 2.10 vs. 36.8 ± 16.8) and lung injury lower as well (1.8 ± 1.6 vs. 6.0 ± 1.2). Double-positive area fractions were higher in AP lambs (0.012 ± 0.003) than early (0.003 ± 0.0005) and late (0.004 ± 0.002) MV controls. Conclusions Lung development continues and lungs are protected from injury during AP support relative to mechanical ventilation. Level of evidence n/a (basic/translational science). [ABSTRACT FROM AUTHOR]

Background We have shown that rhinovirus, a cause of asthma exacerbation, colocalizes with CD68 + and CD11b + airway macrophages after experimental infection in human subjects. We have also shown that rhinovirus-induced cytokine expression is abolished in Toll-like receptor (TLR2) −/− bone marrow–derived macrophages. Objective We hypothesize that TLR2 + macrophages are required and sufficient for rhinovirus-induced airway inflammation in vivo . Methods Naive and ovalbumin (OVA)–sensitized and challenged C57BL/6 wild-type and TLR2 −/− mice were infected with RV1B, followed by IgG or anti-TLR2, to determine the requirement and sufficiency of TLR2 for rhinovirus-induced airway responses. Bone marrow chimera experiments using OVA-treated C57BL/6 and TLR2 −/− mice were also performed. Finally, naive TLR2 −/− mice underwent intranasal transfer of bone marrow–derived wild-type macrophages. Results RV1B infection of naive wild-type mice induced an influx of airway neutrophils and CD11b + exudative macrophages, which was reduced in TLR2 −/− mice. After allergen exposure, rhinovirus-induced neutrophilic and eosinophilic airway inflammation and hyperresponsiveness were reduced in TLR2 −/− and anti-TLR2–treated mice. Transfer of TLR2 −/− bone marrow into wild-type, OVA-treated C57BL/6 mice blocked rhinovirus-induced airway responses, whereas transfer of wild-type marrow to TLR2 −/− mice restored them. Finally, transfer of wild-type macrophages to naive TLR2 −/− mice was sufficient for neutrophilic inflammation after rhinovirus infection, whereas macrophages treated with IL-4 (to induce M2 polarization) were sufficient for eosinophilic inflammation, mucous metaplasia, and airways hyperresponsiveness. Conclusions TLR2 is required for early inflammatory responses induced by rhinovirus, and TLR2 + macrophages are sufficient to confer airway inflammation to TLR2 −/− mice, with the pattern of inflammation depending on the macrophage activation state. [ABSTRACT FROM AUTHOR]

Background Periostin, a secreted extracellular matrix protein, has been localized to deposits of subepithelial fibrosis in asthmatic patients, and periostin levels have been linked to increases in IL-13. Objective We hypothesized that periostin is required for airway inflammatory responses to a physiologic aeroallergen, house dust mite (HDM). Methods We studied F4-F6 B6;129- Postn tm1Jmol /J wild-type ( Postn +/+ ) and null ( Postn −/− ) mice, as well as C57BL/6 mice treated with either IgM or OC-20 periostin neutralizing antibody. Mice were exposed to 5 doses of HDM intranasally over a 16-day period. Results HDM increased airways responsiveness in Postn +/+ but not Postn −/− mice. In addition, HDM-treated C57BL/6 mice injected with OC-20 had lower airways responsiveness than HDM-treated mice injected with IgM. Compared with Postn +/+ mice, Postn −/− mice showed decreases in HDM-induced inflammation and mucous metaplasia, as well as reduced IL-4, IL-25, CD68, Gob5, and periostin mRNA expression. OC-20 antibody produced similar results. HDM exposure increased periostin expression in the airway epithelium, subepithelium, smooth muscle and inflammatory cells. OC-20 blocked the HDM-induced IgE response, and T cells incubated with dendritic cells (DCs) from Postn −/− mice or treated with OC-20 showed deficient DNA synthesis and IL-13 responses compared with T cells incubated with wild-type DCs. Finally, adoptive transfer of bone marrow–derived DCs from Postn +/+ mice was sufficient to promote allergic responses in F6 Postn −/− littermates. Conclusions In mice, periostin is required for maximal airways hyperresponsiveness and inflammation after HDM sensitization and challenge. Periostin is required for maximal HDM-induced T-cell responses. [ABSTRACT FROM AUTHOR]

Background Early-life human rhinovirus infection has been linked to asthma development in high-risk infants and children. Nevertheless, the role of rhinovirus infection in the initiation of asthma remains unclear. Objective We hypothesized that, in contrast to infection of mature BALB/c mice, neonatal infection with rhinovirus promotes an IL-25-driven type 2 response, which causes persistent mucous metaplasia and airways hyperresponsiveness. Methods Six-day-old and 8-week-old BALB/c mice were inoculated with sham HeLa cell lysate or rhinovirus. Airway responses from 1 to 28 days after infection were assessed by using quantitative PCR, ELISA, histology, immunofluorescence microscopy, flow cytometry, and methacholine responsiveness. Selected mice were treated with a neutralizing antibody to IL-25. Results Compared with mature mice, rhinovirus infection in neonatal mice increased lung IL-13 and IL-25 production, whereas IFN-γ, IL-12p40, and TNF-α expression was suppressed. In addition, the population of IL-13-secreting type 2 innate lymphoid cells (ILC2s) was expanded with rhinovirus infection in neonatal but not mature mice. ILC2s were the major cell type secreting IL-13 in neonates. Finally, anti-IL-25 neutralizing antibody attenuated ILC2 expansion, mucous hypersecretion, and airways responsiveness. Conclusions These findings suggest that early-life viral infection could contribute to asthma development by provoking age-dependent, IL-25-driven type 2 immune responses. [ABSTRACT FROM AUTHOR]

Early-life wheezing-associated respiratory tract infection by rhinovirus (RV) is a risk factor for asthma development. Infants are infected with many different RV strains per year. We previously showed that RV infection of 6-day-old BALB/c mice induces a mucous metaplasia phenotype that is dependent on type 2 innate lymphoid cells (ILC2s). We hypothesized that early-life RV infection alters the response to subsequent heterologous infection, inducing an exaggerated asthma-like phenotype. Wild-type BALB/c mice and Rora fl/fl Il7r cre mice lacking ILC2s were treated as follows: (1) sham on day 6 of life plus sham on day 13 of life, (2) RV-A1B on day 6 plus sham on day 13, (3) sham on day 6 plus RV-A2 on day 13, and (4) RV-A1B on day 6 plus RV-A2 on day 13. Mice infected with RV-A1B at day 6 and sham at day 13 showed an increased number of bronchoalveolar lavage eosinophils and increased expression of IL-13 mRNA but not expression of IFN-γ mRNA (which is indicative of a type 2 immune response), whereas mice infected with sham on day 6 and RV-A2 on day 13 of life demonstrated increased IFN-γ expression (which is a mature antiviral response). In contrast, mice infected with RV-A1B on day 6 before RV-A2 infection on day 13 showed increased expression of IL-13, IL-5, Gob5, Muc5b, and Muc5ac mRNA; increased numbers of eosinophils and IL-13–producing ILC2s; and exaggerated mucus metaplasia and airway hyperresponsiveness. Compared with Rora fl/fl mice, Rora fl/fl Il7r cre mice showed complete suppression of bronchoalveolar lavage eosinophils and mucous metaplasia. Early-life RV infection alters the response to subsequent heterologous infection, inducing an intensified asthma-like phenotype that is dependent on ILC2s. [ABSTRACT FROM AUTHOR]

We examined the role of glycogen synthase kinase-3β (GSK-3β) inhibition in airway smooth muscle hypertrophy, a structural change found in patients with severe asthma. LiCl, SB216763, and specific small interfering RNA (siRNA) against GSK-3β, each of which inhibit GSK-3β activity or expression, increased human bronchial smooth muscle cell size, protein synthesis, and expression of the contractile proteins α-smooth muscle actin, myosin light chain kinase, smooth muscle myosin heavy chain, and SM22. Similar results were obtained following treatment of cells with cardiotrophin (CT)-1, a member of the interleukin-6 superfamily, and transforming growth factor (TGF)-β, a proasthmatic cytokine. GSK-3β inhibition increased mRNA expression of α-actin and transactivation of nuclear factors of activated T cells and serum response factor. siRNA against eukaryotic translation initiation factor 2Bϵ (eIF2Bϵ) attenuated LiCl- and SB216763-induced protein synthesis and expression of β-actin and SM22, indicating that eIF2B is required for GSK-3β-mediated airway smooth muscle hypertrophy. eIF2Bϵ; siRNA also blocked CT-1- but not TGF-β-induced protein synthesis. Infection of human bronchial smooth muscle cells with pMSCV GSK-3β-A9, a retroviral vector encoding a constitutively active, nonphosphorylatable GSK-3β, blocked protein synthesis and α-actin expression induced by LiCl, SB216763, and CT-1 but not TGF-β. Finally, lungs from ovalbumin-sensitized and -challenged mice demonstrated increased β-actin and CT-1 mRNA expression, and airway myocytes isolated from ovalbumin-treated mice showed increased cell size and GSK-3β phosphorylation. These data suggest that inhibition of the GSK-3β/eIF2Bϵ translational control pathway contributes to airway smooth muscle hypertrophy in vitro and in vivo. On the other hand, TGF-β-induced hypertrophy does not depend on GSK-3β/eIF2B signaling. [ABSTRACT FROM AUTHOR]

Rhinovirus (RV) is a common cause of asthma exacerbations. The signaling mechanisms regulating RV-induced airway epithelial cell responses have not been well studied. We examined the role of phosphatidylinositol (PI) 3-kinase in RV-induced interleukin (IL)-8 expression. Infection of 16HBE14o- human bronchial epithelial cells with RV39 induced rapid activation of PI 3-kinase and phosphorylation of Akt, a downstream effector of PI 3-kinase. RV39 also colocalized with cit-Akt-PH, a citrogen-tagged fluorescent fusion protein encoding the pleckstrin homology domain of Akt, indicating that 3-phosphorylated PI accumulates at the site of RV infection. Inhibition of PI 3-kinase and Akt attenuated RV39-induced NF-κB transactivation and IL-8 expression. Inhibition of PI 3-kinase also blocked internalization of labeled RV39 into 16HBE14o- cells, suggesting that the requirement of PI 3-kinase for RV39-induced IL-8 expression, at least in part, relates to its role in viral endocytosis. [ABSTRACT FROM AUTHOR]