Fig. 7

Lactobacillus cultures producing high levels of LA upregulate tight junction gene expression. VK2 epithelial cells were treated with media containing 20% (v/v) filtered supernatant from cultures of L. crispatus, L. jensenii, L. iners or G. vaginalis bacteria. The impact of treatment on expression of key tight junction genes was analysed by RNA-Seq, and volcano plots of changes in expression following treatment are shown in (A), with red dots indicating significantly DEGs (FDR < 0.05). B Fold change in expression of claudin-4 (CLDN4), occludin (OCLN), zona occludens-2/tight junction protein-2 (TJP2) and F11R genes relative to cells treated with media alone (mean, from n = 3 replicates; *, ** and ***false discovery rate < 0.5, 0.01 and 0.001, respectively). C Concentration of total lactate (black bars) and protonated LA (grey bars) in treatment media, the latter calculated using the Henderson-Hasselbalch equation and the treatment media pH (range 6.6–7.1). Values were normalised to account for slight variations in growth rate of bacterial cultures