Effect of 17β‑estradiol on a humanvaginal Lactobacillus crispatusstrain

By Maximilien Clabaut
Amandine Suet
Pierre-Jean Racine
Ali Tahrioui
Julien Verdon
Olivier Maillot
Agathe Le Tirant
Madina Karsybayeva
Coralie Kremser
Gérard Redziniak
Cécile Duclairoir‑Poc
Chantal Pichon
Sylvie Chevalier
Marc G. J. Feuilloley

Lactobacilli and estrogens play essential roles in vaginal homeostasis. We investigated the potential
direct effect of 17β-estradiol on a vaginal strain of Lactobacillus crispatus, the major bacterial species
of the vaginal microbiota. 17β-estradiol (10–6 to 10–10 M) had no effect on L. crispatus growth, but
markedly affected the membrane dynamics of this bacterium. This effect appeared consistent with
a signal transduction process. The surface polarity and aggregation potential of the bacterium were
unaffected by exposure to 17β-estradiol, but its mean size was significantly reduced. 17β-estradiol
also promoted biosurfactant production by L. crispatus and adhesion to vaginal VK2/E6E7 cells, but
had little effect on bacterial biofilm formation activity. Bioinformatic analysis of L. crispatus identified
a membrane lipid raft–associated stomatin/prohibitin/flotillin/HflK domain containing protein as a
potential 17β-estradiol binding site. Overall, our results reveal direct effects of 17β-estradiol on L.
crispatus. These effects are of potential importance in the physiology of the vaginal environment,
through the promotion of lactobacillus adhesion to the mucosa and protection against pathogens.