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Identification of neutral endopeptidase mRNA in human nasal mucosa
J N Baraniuk1, K Ohkubo, O J Kwon
1Division of Rheumatology, Immunology, and Allergy, Georgetown University, Washington, DC 20007.
Abstract:
Neutral endopeptidase (NEP) may regulate peptide-induced inflammation in the upper respiratory tract. NEP mRNA was detected by Northern blotting in poly(A)+ mRNA prepared from human turbinates. NEP mRNA bands were detected at 3.9 and 1.8 kb. In situ hybridization identified NEP mRNA in epithelial cells, serous cells of submucosal glands, and vessel walls. The vacuoles of goblet and mucous cells were not stained, but it is likely that the cytoplasm of these cells contained some NEP mRNA. Radioactive in situ hybridization with 35S-UTP appeared to be more sensitive than nonradioactive in situ hybridization with biotin-UTP and immunogold detection. The NEP mRNA-containing cells identified by in situ hybridization were the same as those identified by immunohistochemistry to contain immunoreactive NEP. These NEP-containing cells have been previously shown to possess peptide receptors. This is consistent with the hypothesis that NEP on cells bearing peptide receptors may regulate neuropeptide-induced inflammation in human nasal mucosa.
Insights
Neutral endopeptidase (NEP) in the nasal mucosa may control inflammation. This enzyme, found in specific cells, is linked to peptide receptors, suggesting a role in regulating peptide-induced inflammation.
Area of Science:
- Molecular Biology
- Immunology
- Otorhinolaryngology
Background:
- Neutral endopeptidase (NEP) is implicated in regulating peptide-induced inflammation within the upper respiratory tract.
- Understanding the localization and function of NEP in nasal tissues is crucial for addressing inflammatory conditions.
Purpose of the Study:
- To detect and localize Neutral endopeptidase (NEP) mRNA in human nasal turbinates.
- To investigate the relationship between NEP-expressing cells and peptide receptors in the nasal mucosa.
- To support the hypothesis that NEP regulates neuropeptide-induced inflammation in the nasal mucosa.
Main Methods:
- Northern blotting was used to detect NEP mRNA in poly(A)+ mRNA from human turbinates.
- In situ hybridization (radioactive and nonradioactive) identified NEP mRNA localization in various nasal cell types.
- Immunohistochemistry was employed to detect immunoreactive NEP, correlating with mRNA findings.
Main Results:
- NEP mRNA was detected at 3.9 and 1.8 kb in human turbinate mRNA.
- In situ hybridization localized NEP mRNA in epithelial cells, serous cells of submucosal glands, and vessel walls.
- NEP mRNA-containing cells overlapped with cells expressing immunoreactive NEP and known peptide receptors.
Conclusions:
- Neutral endopeptidase (NEP) mRNA is present in key cell types within the human nasal mucosa.
- The co-localization of NEP with peptide receptors supports its role in modulating neuropeptide-induced inflammation.
- NEP is a potential therapeutic target for inflammatory conditions of the upper respiratory tract.