Table 1.
Studies assessing the expression of aquaporins (AQPs) in normal respiratory epithelium of the nasal cavity.
| Authors and Reference | Study Design | Species and/or Tissue Type | Detection Method | Target AQPs | Results/Conclusion |
|---|---|---|---|---|---|
| Nielsen et al. [14] | Animal tissue study | Rats; respiratory tract, glandular tissues | Immunocyto-chemistry, immunoelectron microscopy | Expression and localization of AQP1, -3, -4, -5 | AQP1: nasopharyngeal vascular endothelium and fibroblasts AQP5: apical plasma membranes of secretory epithelium in upper airway and salivary glands AQP3: basal cells of nasopharyngeal epithelium, basolateral membranes of surface epithelial cells of the nasal conchus AQP4: nasopharyngeal epithelium, nasal conchus |
| Ablimit et al. [15] | Animal tissue study | Rats; nasal olfactory and respiratory mucosae) | Immunocyto-chemistry, immunoblotting | Expression and localization of AQP1, -3, -4, -5 | AQP1: endothelial cells of blood vessels and surrounding connective tissue cells AQP3: mostly restricted to basal cells, relatively weak expression in ciliated columnar cells AQP4: abundant in cells of the respiratory epithelium, such as ciliated columnar cells and basal cells AQP5: apical side of glandular cells |
| Sakai et al. [16] | Animal tissue study | Mice | qRT-PCR | Expression of AQP0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -11, -12 | The genes for AQP1, -3, -4, -5, and -11 were notably expressed in the nasal epithelium. |
| Maeda et al. [17] | Animal tissue study | Musk shrew (Suncus murinus), rat | Immunohisto-chemistry, immunoblotting | Expression of AQP1, -3, -4, -5 | Musk shrew: AQP1, -3, -4, -5 was observed but only a small amount of AQP3, -4, -5 was found. Rat: AQP1, -3, -4, -5 are observed, and AQP3,4 is particularly abundant. |
| Vesterdorfet al. [18] | Animal tissue study | Sheep (Ovis aries) | Immunohisto-chemistry | AQP1, -3, -5 | AQP1: connective tissue, vascular endothelial cells, glandular acini AQP3: ciliated columnar epithelial cells (basolaterally), basal cells AQP5: glandular acini (apically), glandular duct cells, ciliated columnar epithelial cells (apically) |
| Seno et al. [19] | Human tissue study | Human (normal control vs. AR vs. CRSwNP) | RT-PCR, immunoblotting, immunohistochemistry | AQP1, -2, -3, -4, -5 | AQP1: fibroblasts (especially in the subepithelial area), endothelial cells of blood vessels AQP2: cytoplasm of epithelial cells and acinar cells AQP3: basolateral sites of epithelial cells and acinar cells AQP4: basolateral sites of acinar cells AQP5: apical sites of epithelial cells and acinar cells |
| Frauen-felder et al. [20] | Human tissue study | Human (normal control vs. CRSwNP vs. CRSsNP) | RT-PCR, immunohistochemistry | AQP0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12b | AQP1: vasculature and connective tissue AQP3: basolateral membranes of both surface and glandular epithelium > apical membrane and cell cytoplasm AQP4: apical membrane of the surface epithelium, connective tissue AQP5: surface epithelium (apical and basolateral membranes > cytoplasm), glandular epithelium (apical membranes > basolateral membranes and cytoplasm) AQP7 and 11: cytoplasm of the surface and glandular epithelium |
| Matsuzaki et al. [21] | Animal tissue study | Rats | Immunoblotting, immuno-fluorescence microscopy, immunoelectron microscopy | AQP3 | AQP3: pseudostratified ciliated epithelium in the nasal cavity |
AQP, aquaporin; qRT-PCR, quantitative reverse transcription polymerase chain reaction; AR, allergic rhinitis; CRSwNP, chronic rhinosinusitis with nasal polyp; CRSsNP, chronic rhinosinusitis without nasal polyp.