RESUMO
BACKGROUND: Nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are newly discovered cytosolic receptors belonging to the pattern-recognition receptor family. They detect various pathogen-associated molecular patterns, triggering an immune response. The knowledge about these receptors, and their role in health and disease, is limited. The aim of the present study was to characterize the expression of NOD1, NOD2, and NALP3 in the human upper airways. METHODS: Surgical samples were obtained from patients with tonsillar disease (n = 151), hypertrophic adenoids (n = 9), and nasal polyposis (n = 24). Nasal biopsies were obtained from healthy volunteers (n = 10). The expression of NOD1, NOD2, and NALP3 was analyzed using real-time PCR and immunohistochemistry. RESULTS: Expression of NOD1, NOD2, and NALP3 mRNA and protein were seen in all tissue specimens. The NLR mRNA was found to be higher in nasal polyps than in normal nasal mucosa, and local steroid treatment reduced the NLR expression in polyps. In contrast, tonsillar infection with Streptococcus pyogenes or Haemophilus influenzae did not affect the NLR expression. CONCLUSIONS: The present study demonstrates the presence of NLRs in several upper airway tissues and highlights a potential role of NLRs in chronic rhinosinusitis with polyps.
Assuntos
Pólipos Nasais/etiologia , Proteínas Adaptadoras de Sinalização NOD/fisiologia , Sistema Respiratório/química , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Transporte/análise , Proteínas de Transporte/genética , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Imunidade Inata , Masculino , Pessoa de Meia-Idade , Proteína 3 que Contém Domínio de Pirina da Família NLR , Pólipos Nasais/química , Proteínas Adaptadoras de Sinalização NOD/análise , Proteínas Adaptadoras de Sinalização NOD/genética , Proteína Adaptadora de Sinalização NOD1/análise , Proteína Adaptadora de Sinalização NOD1/genética , Proteína Adaptadora de Sinalização NOD2/análise , Proteína Adaptadora de Sinalização NOD2/genética , RNA Mensageiro/análise , Distribuição Tecidual , Adulto JovemRESUMO
BACKGROUND: Recently, a new set of pattern-recognition receptors, the nucleotide-binding oligomerization domain (Nod)-like receptors (NLRs), have emerged. Their activation, either by allergens or microbes, triggers an inflammatory response. The knowledge about NLRs in human airways is limited. AIM OF THE STUDY: To investigate presence of NLRs in the human nose of healthy individuals and patients with intermittent allergic rhinitis outside and during pollen season. METHODS: The expression of Nod1, Nod2, and Nalp3 in nasal biopsies was determined with real-time RT-PCR and immunohistochemistry. Cultured primary human nasal epithelial cells (HNECs) were analyzed using real-time RT-PCR and flow cytometry to further verify the presence of NLRs in the epithelium. RESULTS: Immunohistochemical analysis revealed presence of Nod1, Nod2, and Nalp3 in the nasal epithelium. This was corroborated in cultured HNECs. Patients suffering from symptomatic allergic rhinitis exhibited lower Nod1 and Nalp3 mRNA levels than both controls and patients during pollen season. Nod2 expression was found in all specimens tested, but no differences were seen between the three groups. CONCLUSION: Nod1, Nod2, and Nalp3 receptors were found to be present in the human nose. The expression of Nod1 and Nalp3 were down-regulated during pollen season among patients with allergic rhinitis. This opens up for new insights and novel therapeutic strategies in inflammatory airway disease.