Fetal response to placental dysfunction leads to 5-hmeC and H2A.Z/H3 acetylation in NOS3 while short-termed mRNA boost entails deferred self-attenuation

Results In human fetuses NOS3 expression directly correlated with 5-hydroxymethylcytosine levels as well as H3K9ac and H2A.Zac at the transcription start site. Using an in vitro model for placental dysfunction we confirmed the dynamic NOS3 response and histone acetylation patterns. Concomitantly we recognized massive turnover of Stat3 at a discrete binding site in the NOS3 promoter upon hypoxic conditions. Moreover, knock-down experiments targeting either STAT3 or NOS3 provided strong evidence for a functional NOS3 and STAT3 relationship. Interestingly, induced hyperacetylation and in vitro reporter assays showed that NOS3 expression becomes self-attenuated by co-expression of intronic 27nt-ncRNA modulating STAT3 signaling.