An All-Human Culture Model Supporting Human B Lymphopoesis

Abstract

Pregnancy is a complex process where several physiological pathways interact. The down-regulated inflammatory response and the abundance of anti-inflammatory molecules during gestation may explain the acceptance of the fetus and the lack of immune response against it, even though it is a foreign tissue for the mother. NF-κB is a key regulator of the transcription of inflammatory genes, such as IL-8, IL-1β, TNF-α, or IL-6. Increased NF-κB activity that leads to the production of proinflammatory cytokines may induce obstetric disorders, such as preterm birth or abortion. Low activity of this transcription factor is associated with the beneficial anti-inflammatory environment during fetus development until delivery. Galectin-1 (Gal-1) is a lectin-type glycan-binding protein that is able to down-regulate inflammation. It has been shown that Gal-1 is abundantly expressed at the feto-maternal interface in humans, where it promotes maternal immune tolerance to the fetal semi-allograft. Gal-1 tolerance-promoting mechanisms have been established for adaptive immune cells, such as T cells and dendritic cells. However, the role of this lectin has not been established in non-immune cells at the feto-maternal interface. Here, we determined that Gal-1 is able to block the stimulating effect of LPS on IL-6 in human decidua cells. Our results show that Gal-1 acts by inhibiting the stimulation of the LPS-induced IκBζ expression, an NF-κB regulator involved in IL-6 gene transcription.