TY - JOUR T1 - Neither non-toxigenic <em>Staphylococcus aureus</em> nor commensal <em>S</em>. <em>epidermidi</em> activates NLRP3 inflammasomes in human conjunctival goblet cells JF - BMJ Open Ophthalmology DO - 10.1136/bmjophth-2017-000101 VL - 2 IS - 1 SP - e000101 AU - Dayu Li AU - Robin R Hodges AU - Paulo Bispo AU - Michael S Gilmore AU - Meredith Gregory-Ksander AU - Darlene A Dartt Y1 - 2017/11/01 UR - http://bmjophth.bmj.com/content/2/1/e000101.abstract N2 - Purpose The conjunctiva is a wet mucosal surface surrounding the cornea that is continuously exposed to pathogens. Nevertheless, persistent inflammation is not observed. We examined if the NOD-like receptor pyrin domain 3 (NLRP3) inflammasome functions as a sensor that distinguishes commensal and non-pathogenic bacteria from pathogenic bacteria in human conjunctival goblet cells.Methods Goblet cells were grown from human conjunctiva and co-cultured with commensal Staphylococcus epidermidis, isogenic non-toxigenic S. aureus ACL135 and as a control toxigenic S. aureus RN6390. Activation of the NLRP3 inflammasome was determined by measuring changes in NF-κB activity, expression of pro-interleukin (IL)-1β and NLRP3, activation of caspase-1 and secretion of mature IL-1β. Goblet cell mucin secretion was measured in parallel.Results While all three strains of bacteria were able to bind to goblet cells, neither commensal S. epidermidis nor isogenic non-toxigenic S. aureus ACL135 was able to stimulate an increase in (1) NF-κB activity, (2) pro-IL-1β and NLRP3 expression, (3) caspase-1 activation, (4) mature IL-1β and (5) mucin secretion. Toxigenic S. aureus, the positive control, increased these values: knockdown of NLRP3 with small interfering RNA (siRNA) completely abolished the toxigenic S. aureus-induced expression of pro-IL-1β and secretion of mature IL-1β.Conclusions We conclude that NLRP3 serves as a sensor capable of discriminating commensal and non-pathogenic bacteria from pathogenic bacteria in conjunctival goblet cells, and that activation of the NLRP3 inflammasome induced by pathogenic bacteria mediates secretion of both mature IL-1β and large secretory mucins from these cells. ER -