Microfluidic Co-Culture Platform to Recapitulate the Maternal-Placental-Embryonic Axis.

Safety assessment of the effects of developmental toxicants on pregnant women is challenging, and systemic effects in embryo-maternal interactions are largely unknown. However, most developmental toxicity studies rely on animal trials, while in vitro platforms that recapitulate the maternal-placental-embryonic axis are missing. Here, the development of a dedicated microfluidic device for co-cultivation of a placental barrier and 3D embryoid bodies to enable systemic toxicity testing at the embryo-maternal interface is reported. The microfluidic platform features simple handling and recuperation of both tissue models, which facilitates post-hoc in-depth analysis at the tissue and single-cell level. Gravity-driven flow enables inter-tissue communication through the liquid phase as well as simple and robust operation and renders the platform parallelizable. As a proof of concept and to demonstrate platform use for systemic embryotoxicity testing in vitro, maternal exposure to plastic microparticles is emulated, and microparticle effects on the embryo-placental co-culture are investigated.

The iron-sulphur cluster in human DNA2 is required for all biochemical activities of DNA2.

The nuclease/helicase DNA2 plays important roles in DNA replication, repair and processing of stalled replication forks. DNA2 contains an iron-sulphur (FeS) cluster, conserved in eukaryotes and in a related bacterial nuclease. FeS clusters in DNA maintenance proteins are required for structural integrity and/or act as redox-sensors. Here, we demonstrate that loss of the FeS cluster affects binding of human DNA2 to specific DNA substrates, likely through a conformational change that distorts the central DNA binding tunnel. Moreover, we show that the FeS cluster is required for DNA2's nuclease, helicase and ATPase activities. Our data also establish that oxidation of DNA2 impairs DNA binding in vitro, an effect that is reversible upon reduction. Unexpectedly, though, this redox-regulation is independent of the presence of the FeS cluster. Together, our study establishes an important structural role for the FeS cluster in human DNA2 and discovers a redox-regulatory mechanism to control DNA binding.