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Epithelial disruptions, but not immune cell invasion, induced secretory dysfunction following innate immune activation in a novel model of acute salivary gland injury
Author(s) -
Shaalan Abeer,
Carpenter Guy,
Proctor Gordon
Publication year - 2018
Publication title -
journal of oral pathology and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 83
eISSN - 1600-0714
pISSN - 0904-2512
DOI - 10.1111/jop.12663
Subject(s) - innate immune system , immune system , biology , saliva , immunology , salivary gland , microbiology and biotechnology , biochemistry
Background Salivary gland (SG) injurious agents are all translated into loss of salivation (xerostomia). An association has been established between activation of innate immunity and SG injury and dysfunction. However, it remains unclear how the secretory epithelia respond by halting saliva production. Methods C57BL/6 submandibular glands (SMGs) were acutely challenged using a single dose of the innate immune stimulant: polyinosinic‐polycytidylic acid (poly (I:C)). Secretory capacity of the infected SMGs was substantiated by assessing the flow rate in response to pilocarpine stimulation. Depletion of the acute inflammatory cells was achieved by pre‐treating mice with RB6‐8C5 depletion antibody. Flow cytometry, histology and immunohistochemistry were conducted to verify the immune cell depletion. Epithelial expression of saliva‐driving molecules: muscarinic 3 receptor (M3R), aquaporin 5 water channel (AQP5), Na‐K‐CL‐Cotransporter 1 (NKCC1) and transmembrane member 16A (TMEM16A), was characterized using RT‐qPCR and immunohistochemistry. Tight junction (TJ) protein; zonula occludens (ZO‐1) and basement membrane (BM) protein; and laminin were assessed by immunohistochemistry. Results Innate immune challenge prompted dysfunction in the exocrine SGs. Dysregulated gene and protein expression of molecules that drive saliva secretion was substantiated. Aberrant expression of TJ and BM proteins followed innate immune activation. Hyposalivation in the current model was independent of myeloperoxidase (MPO)‐positive, acute inflammatory cells. Conclusions In this study, we developed a novel injury model of the SGs, featuring acute secretory dysfunction and immediate structural disruptions. Our results ruled out the injurious role of aggressively infiltrating inflammatory cells.