Expression and localization of surfactant proteins in human nasal epithelium

Abstract

Surfactant proteins (SPs), designated SP-A, SP-B, SP-C, and SP-D, play an important role in surfactant metabolism and host defense mechanisms in the lung. This study investigates expression of the different SP types in human nasal mucosa and cultured normal human nasal epithelial (NHNE) cells and whether the expression of SP mRNA is influenced by the degree of mucociliary differentiation. RT-PCR was performed with mRNA from cultured NHNE cells and nasal mucosa. Immunohistochemical staining for SPs was performed on nasal mucosa specimens. Western blot analysis was performed on cell lysates from cultured NHNE cells. SP-A2, SP-B, and SP-D mRNAs were expressed in normal NHNE cells and human nasal mucosa. SPs were localized in ciliated cells of the surface epithelium and serous acini of the submucosal glands. SP-A, SP-B, and SP-D proteins were expressed in cultured NHNE cells. The degree of mucociliary differentiation influenced expression of the SP gene. We demonstrate that SP-A, SP-B, and SP-D are expressed in human nasal mucosa and cultured NHNE cells. Further study of the functional role of SPs in the upper airway is required.

Proteomic analysis of pediatric sinonasal secretions shows increased MUC5B mucin in CRS

“…Several of the innate immunity proteins that show increased expression in CRS secretions in our study, e.g., BPIFA1, DMBT1, S100A8, S100A9, LTF, MYH9, and IGHA1, have been reported as being dysregulated in studies of CRS nasal lavage fluid or sinus tissues (6,11,(16)(17)(18)(19). These proteins are discussed below.…”

Surfactant Proteins A, B, C and D in the Human Nasal Airway: Associated with Mucosal Glands and Ciliated Epithelium but Absent in Fluid-Phase Secretions and Mucus

“…In relation to the nasal upper airways, a few studies found expression and localization of SP-A, -B and -D in human nasal epithelium [4,17,18], and, very recently, Schicht et al [12] have confirmed and extended these studies by finding that SP-C was also associated with nasal epithelium. All 4 proteins show more or less the same pattern of localization with prominent immunoreactivity associated with submucosal glands, being more specific within the serous acini but less so within the mucous acini.…”

“…Alveolar type II cells are the source of surfactant synthesis in the lower airways. SP-A, -B and -D are also synthesized by airway cells, such as Clara cells and submucosal cells [4,5,6]. …”

“…To date, several studies have demonstrated a local expression of these proteins in other organs of the human body, such as the human lacrimal system and tear fluid [7,8], the human organ of Corti, the eustachian tube and the kidney [9], various structures in the skin [10], the human parotid and submandibular glands [11] as well as in epithelial cells in a variety of tissues throughout the body [5]. Previous studies have demonstrated the expression of SP-A, -B and -D in human sinonasal tissue [4], and the presence of SP-C has recently been described in a study by Schicht et al [12]. In the lung, it is well known that SP-A and SP-D expression is altered during inflammation and infectious diseases [13,14].…”

Surfactant-Associated Protein A Provides Critical Immunoprotection in Neonatal Mice

“…Other examples are based on association, specifically genetic association studies. For example, SP-A is found in the human nasal epithelium (27). A polymorphism of the SP-A2 gene is associated with increased risk of meningococcemia, an infectious process that requires colonization of the nasopharynx by Neisseria meningitides (21).…”