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Novel role of surfactant protein A in bacterial sinusitis
Author(s) -
Noutsios George T.,
Willis Amanda L.,
Ledford Julie G.,
Chang Eugene H.
Publication year - 2017
Publication title -
international forum of allergy and rhinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.503
H-Index - 46
eISSN - 2042-6984
pISSN - 2042-6976
DOI - 10.1002/alr.21985
Subject(s) - innate immune system , medicine , downregulation and upregulation , surfactant protein a , surfactant protein d , western blot , nasal polyps , immunology , inflammation , immune system , sinusitis , microbiology and biotechnology , ex vivo , lung , pathology , biology , in vivo , gene , biochemistry
Background Chronic rhinosinusitis (CRS) is a common inflammatory disorder of the upper airway characterized by chronic inflammation and significant sinonasal remodeling. CRS is comprised of 2 major subgroups, based on whether polyps are present or absent. In some cases, it is characterized by colonization with opportunistic pathogens such as Pseudomonas aeruginosa (PA), Staphylococcus aureus , and other bacteria. The innate immune system of the sinonasal epithelium is the first line of defense against inhaled pathogens. Surfactant protein A (SP‐A) is a member of the collectin family secreted by the airway epithelia and plays a critical role in airway innate immunity, as it can aggregate bacteria. We hypothesized that SP‐A plays a role in bacterial CRS. Methods Air‐liquid interface (ALI) cultures of nasal epithelial cells were derived from human ex‐vivo healthy and CRS sinus tissues (n = 26) and challenged with PA. SP‐A levels were measured with western blot and quantitative reverse transcript‐polymerase chain reaction (qRT‐PCR) in ALI and sinus tissues. Results We determined that SP‐A: (i) mRNA and protein levels are increased significantly in CRS tissues compared with healthy sinuses; (ii) although primarily expressed in the lung, it is also synthesized and expressed in sinonasal epithelia; (ii) is expressed in the sinuses of an SP‐A humanized transgenic mouse but not in SP‐A knockout mice; (iv) mRNA levels are upregulated significantly during PA challenge, but protein levels are downregulated 4 hours postchallenge and upregulated at 12 hours. Conclusion Our data suggest that SP‐A is expressed in the sinuses and that it plays a role in the sinus innate immune responses during bacterial infections.