Fig. 3. Role of TLR2 activation in L. casei AMBR2-induced epithelial barrier restoration in vitro. (A) Activation of TLR2:TLR6 receptor in transfected HEK293 cells by L. casei AMBR2. Pam2CSK4 and medium were used as positive and negative controls respectively. (B) Effect of 2 hours pre-treatment with human TLR2 polyclonal antibody before incubation with L. casei AMBR2 for 6 hours in ALI cultures of CRSwNP patients (n = 9). (C) Representative immunostainings for occludin and ZO-1 in ALI cultures from CRSwNP patients. White arrows indicate opening of tight junctions (scale bar = 1 μm). Data are presented as mean ± SEM. Two-way ANOVA with post hoc analysis for (B).

TLR, Toll-like receptor; TEER, trans-epithelial electrical resistance; CRSwNP, chronic rhinosinusitis with nasal polyps; ALI, air-liquid interphase; ANOVA, analysis of variance; CFU, colony-forming unit; ZO-1, zonula occludens-1.

^*P < 0.05; ^†P < 0.01; ^‡P < 0.001; ^§P < 0.05.