N/OFQ-NOP System and Airways.

Asthma is a heterogeneous chronic inflammatory disease of the airways. The most prevalent form is atopic asthma, which is initiated by the exposure to (inhaled) allergens. Intermittent attacks of breathlessness, airways hyperresponsiveness, wheezing, coughing, and resultant allergen-specific immune responses characterize the disease. Nociceptin/OFQ-NOP receptor system is able to combine anti-hyperresponsiveness and immunomodulatory actions. In particular, N/OFQ is able to inhibit airways microvascular leakage and bronchoconstriction through a presynaptic and non-opioid mechanism of action that blocks tachykinin release. Moreover, it also acts on allergenic sensitization because it is able to modulate the immune response that triggers the development of airway hyperresponsiveness through an interaction on cell membranes of dendritic cells (DCs) that are generally responsible to start and sustain allergic T helper 2 (TH2)-cell responses to inhaled allergens in asthma. In asthmatic patients, sputum showed elevated N/OFQ levels that are related to increased eosinophil counts. The addition of exogenous N/OFQ in sputum obtained from patients with severe asthma attenuated eosinophils migration and release of inflammatory mediators. These observations confirmed that elevated endogenous N/OFQ levels in asthmatic sputum were lower than the ones required to exert beneficial effects, suggesting that supplementation with exogenous N/OFQ may need. In conclusion, the innovative role of N/OFQ in counteracting airways inflammation/hyperresponsiveness opens new potential targets/strategies in asthma treatment.

Nociceptin/Orphanin Fq in inflammation and remodeling of the small airways in experimental model of airway hyperresponsiveness.

It is widely recognized that airway inflammation and remodeling play a key role not only in the central airway but also small airway pathology during asthma. Nociceptin/Orphanin FQ (N/OFQ), an endogenous peptide, and its receptor N/OFQ peptide (NOP) are involved in airway hyperresponsiveness (AHR). We studied a murine model of AHR in order to understand the role of N/OFQ in the inflammation and remodeling of the small airways. Balb/c mice were sensitized to ovalbumin (OVA). At days 0 and 7 (pre-OVA sensitization) or from day 21 to 23 (post-OVA sensitization), the mice were treated intraperitoneally with N/OFQ or saline solution. After the last OVA challenge, all OVA-sensitized mice were aerosol-challenged with 1% OVA in PBS for 48 h, and then euthanized. Small airway compliance (sCaw ) was measured and lung samples were collected for histological and molecular evaluations such as perimeter and diameter of small airway, total wall area, airway smooth muscle (ASM) thickness and number of alveolar attachments. Both pre- and post-OVA sensitization N/OFQ treatments induced: (1) increases in sCaw ; (2) reduction of the bronchial wall thickness; (3) attenuation of the hyperplastic phase of airway smooth muscle mass; and (4) protection against loss of alveolar attachments compared with saline solution treatments. These results suggest that N/OFQ protects against inflammation, and mechanical damage and remodeling of small airways caused by OVA sensitization, suggesting a new potential therapeutic target for asthma.

Lung Mesenchymal Stem Cells Ameliorate Elastase-Induced Damage in an Animal Model of Emphysema.

Pulmonary emphysema is a respiratory condition characterized by alveolar destruction that leads to airflow limitation and reduced lung function. Although with extensive research, the pathophysiology of emphysema is poorly understood and effective treatments are still missing. Evidence suggests that mesenchymal stem cells (MSCs) possess the ability to engraft the injured tissues and induce repair via a paracrine effect. Thus, the aim of this study was to test the effects of the intratracheal administration of lung-derived mouse MSCs in a model of elastase-induced emphysema. Pulmonary function (static lung compliance) showed an increased stiffness induced by elastase, while morphometric findings (mean linear intercept and tissue/alveolar area) confirmed the severity of alveolar disruption. Contrarily, MSC administration partially restored lung elasticity and alveolar architecture. In the absence of evidence that MSCs acquired epithelial phenotype, we detected an increased proliferative activity of aquaporin 5- and surfactant protein C-positive lung cells, suggesting MSC-driven paracrine mechanisms. The data indicate the mediation of hepatocyte growth factor in amplifying MSC-driven tissue response after injury. Our study shed light on supportive properties of lung-derived MSCs, although the full identification of mechanisms orchestrated by MSCs and responsible for epithelial repair after injury is a critical aspect yet to be achieved.

New Role of Adult Lung c-kit+ Cells in a Mouse Model of Airway Hyperresponsiveness.

Structural changes contribute to airway hyperresponsiveness and airflow obstruction in asthma. Emerging evidence points to the involvement of c-kit+ cells in lung homeostasis, although their potential role in asthma is unknown. Our aim was to isolate c-kit+ cells from normal mouse lungs and to test whether these cells can interfere with hallmarks of asthma in an animal model. Adult mouse GFP-tagged c-kit+ cells, intratracheally delivered in the ovalbumin-induced airway hyperresponsiveness, positively affected airway remodeling and improved airway function. In bronchoalveolar lavage fluid of cell-treated animals, a reduction in the number of inflammatory cells and in IL-4, IL-5, and IL-13 release, along with an increase of IL-10, was observed. In MSC-treated mice, the macrophage polarization to M2-like subset may explain, at least in part, the increment in the level of anti-inflammatory cytokine IL-10. After in vitro stimulation of c-kit+ cells with proinflammatory cytokines, the indoleamine 2,3-dioxygenase and TGFß were upregulated. These data, together with the increased apoptosis of inflammatory cells in vivo, indicate that c-kit+ cells downregulate immune response in asthma by influencing local environment, possibly by cell-to-cell contact combined to paracrine action. In conclusion, intratracheally administered c-kit+ cells reduce inflammation, positively modulate airway remodeling, and improve function. These data document previously unrecognized properties of c-kit+ cells, able to impede pathophysiological features of experimental airway hyperresponsiveness.