Novel role of surfactant protein A in bacterial sinusitis.

TitleNovel role of surfactant protein A in bacterial sinusitis.
Publication TypeJournal Article
Year of Publication2017
AuthorsNoutsios GT, Willis AL, Ledford JG, Chang EH
JournalInt Forum Allergy Rhinol
Date Published2017 09
KeywordsAdult, Aged, Animals, Cells, Cultured, Chronic Disease, Epithelial Cells, Female, Humans, Immunity, Innate, Male, Mice, Inbred C57BL, Mice, Knockout, Middle Aged, Nasal Mucosa, Paranasal Sinuses, Pseudomonas aeruginosa, Pseudomonas Infections, Pulmonary Surfactant-Associated Protein A, Rhinitis, Sinusitis, Young Adult

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.

Alternate JournalInt Forum Allergy Rhinol
PubMed ID28727907
PubMed Central IDPMC5783157
Grant ListU19 AI125357 / AI / NIAID NIH HHS / United States
R01 HL125602 / HL / NHLBI NIH HHS / United States
R01 HL132523 / HL / NHLBI NIH HHS / United States
R00 HL111151 / HL / NHLBI NIH HHS / United States
K08 DE021413 / DE / NIDCR NIH HHS / United States
Faculty Reference: 
Eugene H. Chang, MD