Maternal microbiota communicates with the fetus through microbiota-derived extracellular vesicles
Anna Kaisanlahti, Jenni Turunen, Nadiya Byts, Anatoly Samoylenko, Geneviève Bart, Nikke Virtanen, Mysore V. Tejesvi, Artem Zhyvolozhnyi, Sonia Sarfraz, Sohvi Kumpula, Jenni Hekkala, Sonja Salmi, Olga Will, Johanna Korvala, Niko Paalanne, Pande Putu Erawijantari, Marko Suokas, Tuula Peñate-Medina, Seppo Vainio, Oula Peñate Medina, Leo Lahti, Terhi Tapiainen, Justus Reunanen
Abstract
BACKGROUND: Reports regarding the presence of bacteria in the fetal environment remain limited and controversial. Recently, extracellular vesicles secreted by the human gut microbiota have emerged as a novel mechanism for host-microbiota interaction. We aimed to investigate the presence of bacterial extracellular vesicles in the fetal environment during healthy pregnancies and determine whether extracellular vesicles derived from the gut microbiota can cross biological barriers to reach the fetus. RESULTS: Bacterial extracellular vesicles were detectable in the amniotic fluid of healthy pregnant women, exhibiting similarities to extracellular vesicles found in the maternal gut microbiota. In pregnant mice, extracellular vesicles derived from human maternal gut microbiota were found to reach the intra-amniotic space. CONCLUSIONS: Our findings reveal maternal microbiota-derived extracellular vesicles as an interaction mechanism between the maternal microbiota and fetus, potentially playing a pivotal role in priming the prenatal immune system for gut colonization after birth. Video Abstract.