piperidines and Respiratory-Syncytial-Virus-Infections

Endocannabinoid system plays an important role in pathophysiologic processes such as immune functions and impacts on disease severity. Our previous study showed that cannabinoid receptor 2 (CB2) affects clinical course of respiratory syncytial virus (RSV) infection. In this study, we investigated the role of cannabinoid receptor 1 (CB1) in RSV immunopathology and its therapeutic potential in mice model. To study the role of CB1 receptors in the immunopathology of RSV, CB1 was blocked daily with AM281 as a selective antagonist in Balb/c mice and were infected by intranasal inoculation of RSV-A2 24 h following the first dose of antagonist administration. The potential pharmacological therapeutic effects of cannabinoid receptor activation during RSV infection were studied using JZL184 as a selective indirect agonist, 24 h after infection. Mice were sacrificed on day 5 after infection and experimental analyses were performed to study the CB1 receptor expression, airway immune cell influx, cytokine/chemokine secretion, lung histopathology, and viral load. RSV infection of airways significantly induced the expression of CB1 receptors in lung cells of mice. Blockade of CB1 receptors using AM281 enhanced immune cell influx and cytokine/chemokine production, and aggravated lung pathology. Activation of cannabinoid receptors using JZL184 decreased immune cell influx and cytokine/chemokine production, and alleviated lung pathology. This study and our previous finding indicated that endocannabinoid signaling regulates the inflammatory response to RSV infection, and is a potential therapeutic candidate for alleviation of RSV-associated immunopathology.

Topics: Animals; Benzodioxoles; Bronchoalveolar Lavage Fluid; Chemokine CCL3; Disease Models, Animal; Female; Interferon-gamma; Interleukin-10; Leukocyte Count; Lung; Mice; Mice, Inbred BALB C; Morpholines; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human; Viral Load

We investigated the impact of respiratory syncytial virus (RSV) infection, an important asthma precipitant, on endothelin receptor function and release in sheep bronchial explants. RSV infection was confirmed using polymerase chain reaction and immunohistochemistry. Since sheep airway smooth muscle contains only endothelin-A receptors, sarafotoxin (Stx) S6c did not cause airway contraction. In contrast, sarafotoxin S6c (300 nM) caused contraction in RSV-infected bronchial explants (8 +/- 3% carbachol Emax). However, we could not detect airway smooth muscle endothelin-B receptors in explants using autoradiography. RSV infection per se did not alter the release of immunoreactive endothelin from sheep bronchial explants (control = 11.6 +/- 0.9 pg versus RSV = 12.1 +/- 0.9 pg). Interestingly, dexamethasone (1 microM) alone increased endothelin release in both control (17.9 +/- 2.0 pg) and RSV-infected tissue (18.3 +/- 3.1 pg). The combined presence of protease-activated receptor-2 (PAR-2) ligand (100 microM) and dexamethasone (1 microM) also increased endothelin release from control tissue (17.3 +/- 1.4 pg), but endothelin release was suppressed by PAR-2 ligand in RSV-infected tissue (10.3 +/- 0.8 pg), probably because PAR-2 expression was increased by RSV. In summary, the novel expression of endothelin-B receptors triggered by RSV might be relevant to RSV-associated asthma. Furthermore, activation of airway PAR-2 may be protective in asthma where endothelin levels are elevated in part via endothelin release suppression.

Topics: Animals; Bronchi; Culture Media, Conditioned; Dexamethasone; Dinoprostone; Dose-Response Relationship, Drug; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Indomethacin; Male; Muscle Contraction; Muscle, Smooth; Oligopeptides; Peptides, Cyclic; Piperidines; Receptor, Endothelin A; Receptor, Endothelin B; Receptor, PAR-2; Respiratory Syncytial Virus Infections; Sheep; Time Factors; Tissue Culture Techniques; Viper Venoms

Respiratory syncytial virus (RSV) infection is associated with exaggerated neurogenic inflammation in the airways. This study sought to determine whether irritation of the mucosal sensory fibers affects the recruitment of lymphocytes and monocytes to RSV-infected airways. Pathogen-free rats were inoculated with RSV or with virus-free medium and were injected 5 days later with capsaicin to stimulate airway sensory nerves. Bronchoalveolar lavage was performed 1, 5, or 10 days after nerve stimulation, and samples were analyzed by differential cell count and flow cytometry. Without nerve stimulation, RSV caused a minimal increase in the number of lymphocytes and monocytes above pathogen-free control levels. After nerve stimulation, numerous lymphocytes, predominantly CD4+ T cells, and monocytes were recruited in the airways of infected rats, whereas no difference was found in pathogen-free controls. RSV induced overexpression of the neurokinin 1 (NK1) receptor for substance P on discrete lymphocyte subpopulations within the bronchial-associated lymphoid tissue (BALT), and treatment with a specific NK1 receptor antagonist abolished the recruitment of both lymphocytes and monocytes to infected airways. Our data suggest that airborne irritants stimulating mucosal sensory fibers during RSV infection exert important immunomodulatory effects by attracting to the infected airways selected lymphocyte subpopulations from the local BALT as well as monocytes.

Topics: Adjuvants, Immunologic; Animals; Asthma; Leukocyte Count; Lung; Lymphocyte Subsets; Male; Monocytes; Neurokinin-1 Receptor Antagonists; Neurons, Afferent; Piperidines; Pneumonia, Viral; Rats; Rats, Inbred F344; Receptors, Neurokinin-1; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Specific Pathogen-Free Organisms; Substance P

Cotton rats exposed to continuous small droplet aerosols of 2[[2-[[1-(2-aminoethyl)-4-piperidinyl]amino]-4-methyl-1H-benzimidazol-1-yl]methyl]-6-methyl-3-pyridinol (JNJ 2408068) or its hydrochloric salt for only 15 min, one day prior to virus inoculation or one day after, were significantly protected from pulmonary respiratory syncytial virus (RSV) infection compared to control animals similarly infected but exposed to aerosols of placebo at these times. No evidence of toxicity was seen in any of these animals or in cotton rats administered 10 times the minimum cotton rat efficacious dose (i.e. 10x0.39 mg of active compound per kilogram of body weight) for four continuous days. The marked selective antiviral activity observed in the cotton rats mirrored that seen for these compounds in cytotoxicity and antiviral assays performed against RSV in vitro. Plasma kinetics and tissue distribution of JNJ 2408068 in cotton rats following inhalation were determined in separate experiments performed using conditions similar to those utilized in the in vivo efficacy studies. The data from these experiments indicated that significant levels of the test compound were delivered to the lungs of exposed animals, but that extrapulmonary distribution was limited.

Topics: Administration, Inhalation; Aerosols; Animals; Antiviral Agents; Benzimidazoles; Drug Evaluation, Preclinical; Female; Lung; Male; Piperidines; Pyridines; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Sigmodontinae

Respiratory syncytial virus (RSV) infection in adult rats causes exaggerated inflammation after sensory nerve stimulation in the extrapulmonary, but not in the intrapulmonary airways. The goal of this study was to analyze neurogenic inflammation in weanling F-344 rats infected with RSV 18 +/- 2 d after birth. Five days after RSV inoculation, the extravasation of Evans blue-labeled albumin after nerve stimulation was significantly greater in the intrapulmonary airways of RSV-infected weanling rats than in pathogen-free control rats. In contrast, no difference was found in the extrapulmonary airways. The level of messenger RNA (mRNA) encoding the substance P (SP) receptor (neurokinin 1 [NK1]) increased fourfold in RSV-infected lungs, whereas mRNA encoding the VIPR1 receptor for the antiinflammatory vasoactive intestinal peptide (VIP) increased to a much lesser degree. mRNAs encoding the other neurokinin (NK2) and VIP (VIPR2) receptors were not affected by the virus. Selective inhibition of the NK1 receptor abolished neurogenic inflammation in RSV-infected intrapulmonary airways. Also, neurogenic inflammation and NK1 receptor upregulation in infected lungs were inhibited by prophylaxis with a monoclonal antibody against RSV. These data suggest that RSV lower respiratory tract infection makes the intrapulmonary airways of young rats abnormally susceptible to the proinflammatory effects of SP by selectively upregulating the expression of NK1 receptors.

Topics: Animals; Antibodies, Monoclonal; Body Weight; Cell Line; DNA Primers; Humans; Immunoenzyme Techniques; Lung; Neurogenic Inflammation; Neuropeptides; Piperidines; Rats; Rats, Inbred F344; Receptors, Neurokinin-1; Receptors, Neurokinin-2; Receptors, Vasoactive Intestinal Peptide; Respiratory Syncytial Virus Infections; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Substance P; Up-Regulation