Rationale: Infection with rhinovirus (RV) triggers exacerbations of asthma and chronic obstructive lung disease. Objectives: We sought to develop a mouse model of RV employing RV1B, a minor group serotype that binds to the low-density lipoprotein receptor. Methods: C57BL/6 mice were inoculated intranasally with RV1B, replication-deficient ultraviolet (UV)-irradiated RV1B, or RV39, a major group virus. Measurements and Main Results: Viral RNA was present in the lungs of RV1B-treated mice, but not in those exposed to UV-irradiated RV1B or RV39. Lung homogenates of RV-treated mice contained infectious RV 4 days after inoculation. RV1B exposure induced neutrophilic and lymphocytic airway inflammation, as well as increased lung expression of KC, macrophage-inflammatory protein-2, and IFN-a and IFNb. RV1B-exposed mice showed airway hyperresponsiveness 1 and 4 days after inoculation. UV-irradiated RV1B induced modest neutrophilic airway inflammation and hyperresponsiveness 1 day after exposure. Both RV1B and UV-irradiated RV1B, but not RV39, increased lung phosphorylation of Akt. Confocal immunofluorescence showed colocalization of RV1B and phospho-Akt in the airway epithelium. Finally, pretreatment with the phosphatidylinositol 3-kinase inhibitor LY294002 attenuated chemokine production and neutrophil infiltration. Conclusions: We conclude that RV1B induces airway inflammation in vivo. Evidence is presented that viral replication occurs in vivo and is required for maximal responses. On the other hand, viral replication was not required for a subset of RV-induced responses, including neutrophilic inflammation, airway hyperresponsiveness, and Akt phosphorylation. Finally, phosphatidylinositol 3-kinase/Akt signaling is required for maximal RV1B-induced airway neutrophilic inflammation, likely via its essential role in virus internalization.Keywords: asthma; chronic obstructive pulmonary disease; Akt; low-density lipoprotein receptor Viral infections trigger nearly 80% of asthma exacerbations, and rhinovirus (RV) accounts for the majority of virus-induced exacerbations (1, 2). RV also accounts for a substantial percentage of chronic obstructive pulmonary disease (COPD) exacerbations (3, 4). Understanding of RV-induced exacerbations is incomplete, in part because of the absence of an animal model. Rhinovirus RNA has been detected by polymerase chain reaction (PCR) analysis in lower airway cells from volunteers experimentally infected with RV16 (5, 6) and RV capsid protein has been found in airway epithelial cells, albeit sporadically (6). However, RV has not been cultured from the lower airways of immunocompetent subjects, and therefore the extent to which RV infects or replicates in the lower airways of humans remains unclear.RV, a member of the Picornaviridae family of viruses, is responsible for the majority of common colds. The virus is composed of an icosahedral protein capsid and a positive, singlestranded RNA genome. More than 100 serotypes of RV have been identified. These are divided into two groups on the basis o...

Highlights ► Rhinovirus is responsible for majority of common colds. ► There are no FDA approved drugs are available to treat rhinovirus infection. ► We show that quercetin, a plant flavonoid blocks viral replication in vitro . ► In addition quercetin inhibits virus-stimulated cytokine expression. ► Quercetin also inhibits viral replication and decreasing lung inflammation in vivo .

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-B 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. Rhinovirus (RV)2 is a single-stranded RNA virus from the Picornaviridae family responsible for the majority of common colds. Viral infections trigger the majority of asthma exacerbations (1, 2), and RV accounts for 60% of virus-induced exacerbations (1). RV is also an important trigger of chronic obstructive pulmonary disease (COPD) exacerbations (3, 4). The precise mechanisms by which RV induces asthma or COPD exacerbations are unknown, but numerous studies suggest a role for IL-8, a CXC chemokine with the neutrophil-attractant Glu-Leu-Arg (ELR) motif. IL-8 and neutrophils are found in the nasal secretions and sputum of patients with RV-induced asthma exacerbations (5-9). Further, the number of neutrophils correlates with the level of IL-8 (7, 9). RV induces IL-8 expression in cultured airway epithelial cells (10 -12). Increased neutrophil and IL-8 levels are a feature of asthma (13,14) and COPD exacerbations (15-17). Together, these data suggest that RV may stimulate asthma exacerbations by inducing bronchial epithelial cell production of IL-8, leading to a neutrophilic inflammatory response.The human RVs include more than 100 serotypes that are divided into two groups based on their cellular receptors. Intercellular adhesion molecule (ICAM)-1 is the airway epithelial cell receptor for major subgroup RVs (e.g. RV14, RV16, and RV39), whereas the low density lipoprotein receptor functions as the receptor for minor subgroup RVs (e.g. RV1B and RV2). Thus, antibodies to ICAM-1 inhibit major subgroup RV infection of epithelial cells (18).ICAM-1 is a type I transmembrane glycoprotein belonging to the immunoglobulin superfamily. In endothelial cells, ICAM-1 cross-linking increases phosphorylation and activation of pp60 Src (19,20) and pp125 focal adhesion kinase (21). The p85 regulatory subunit of class 1A PI 3-kinase serves as a substrate for both Src (22) and focal adhesion kinase (23, 24), suggesting that ICAM-1 ligation by RV could also activate PI 3-kinase. Other viruses with different membrane receptors also activate PI 3-kinase. Adenovirus atta...

Together, these data demonstrate that tracheal aspirate fluid from premature, mechanically ventilated infants contains fibroblasts with cell markers and differentiation potential typically found in mesenchymal stem cells.

Severe congenital neutropenia (SCN) is an inborn disorder of granulopoiesis that in many cases is caused by mutations of the ELANE gene, which encodes neutrophil elastase (NE). Recent data suggest a model in which ELANE mutations result in NE protein misfolding, induction of endoplasmic reticulum (ER) stress, activation of the unfolded protein response (UPR), and ultimately a block in granulocytic differentiation. To test this model, we generated transgenic mice carrying a targeted mutation of Elane (G193X) reproducing a mutation found in SCN. The G193X Elane allele produces a truncated NE protein that is rapidly degraded. Granulocytic precursors from G193X Elane mice, though without significant basal UPR activation, are sensitive to chemical induction of ER stress. Basal and stress granulopoiesis after myeloablative therapy are normal in these mice. Moreover, inaction of protein kinase RNAlike ER kinase (Perk), one of the major sensors of ER stress, either alone or in combination with G193X Elane, had no effect on basal granulopoiesis. However, inhibition of the ER-associated degradation (ERAD) pathway using a proteosome inhibitor resulted in marked neutropenia in G193X Elane.