Context.-The placenta is an important component in understanding the fetal response to intrauterine Zika virus infection, but the pathologic changes in this organ remain largely unknown. Hofbauer cells are fetal-derived macrophages normally present in the chorionic villous stroma. They have been implicated in a variety of physiological and pathologic processes, in particular involving infectious agents.Objectives.-To characterize the fetal and maternal responses and viral localization in the placenta following Zika virus transmission to an 11 weeks' gestation fetus. The clinical course was notable for prolonged viremia in the mother and extensive neuronal necrosis in the fetus. The fetus was delivered at 21 weeks' gestation after pregnancy termination.Design.-The placenta was evaluated by using immunohistochemistry for inflammatory cells (macrophages/ monocytes [Hofbauer cells], B and T lymphocytes) and proliferating cells, and an RNA probe to Zika virus. The fetal brain and the placenta were previously found to be positive for Zika virus RNA by reverse transcriptionpolymerase chain reaction.Results.-The placenta demonstrated prominently enlarged, hydropic chorionic villi with hyperplasia and focal proliferation of Hofbauer cells. The degree of Hofbauer cell hyperplasia gave an exaggerated immature appearance to the villi. No acute or chronic villitis, villous necrosis, remote necroinflammatory abnormalities, chorioamnionitis, funisitis, or hemorrhages were present. An RNA probe to Zika virus was positive in villous stromal cells, presumably Hofbauer cells.Conclusions.-Zika virus placental infection induces proliferation and prominent hyperplasia of Hofbauer cells in the chorionic villi but does not elicit villous necrosis or a maternal or fetal lymphoplasmacellular or acute inflammatory cell reaction.

Ser-133 phosphorylation of CREB within the kinase-inducible domain (KID) promotes target gene activation via complex formation with the KIX domain of the coactivator CBP. Concurrent phosphorylation of CREB at Ser-142 inhibits transcriptional induction via an unknown mechanism. Unstructured in the free state, KID folds into a helical structure upon binding to KIX. Using site-directed mutagenesis based on the NMR structure of the KID:KIX complex, we have examined the mechanisms by which Ser-133 and Ser-142 phosphorylation regulate CREB activity. Our results indicate that phospho-Ser-133 stablizes whereas phospho-Ser-142 disrupts secondary structure-mediated interactions between CREB and CBP. Thus, differential phosphorylation of CREB may form the basis by which upstream signals regulate the specificity of target gene activation.

The purpose of this study was to evaluate the influence of endothelial nitric oxide synthase (eNOS) deficiency on fetal growth, perinatal survival, and limb development in a mouse model with a targeted mutagenesis of the Nos3 gene. Wild-type (Nos3+/+) and eNOS-deficient fetuses (Nos3-/-) were evaluated on Gestational Day (E)15 and E17, and newborn pups were observed on Day 1 of life (D1). The average term duration of pregnancy was 19 days. For the evaluation of postnatal development, a breeding scheme consisting of Nos3+/- x Nos3+/- and Nos3-/- x Nos3-/- mice was established, and offspring were observed for 3 wk. Southern blotting was used for genotyping. No significant differences in fetal weight, crown-rump lengths (CRL), and placental weight were seen between Nos3+/+ and Nos3-/- fetuses on E15. By E17, Nos3-/- fetuses showed significantly reduced fetal weights, CRL, and placental weights. This difference in body weight was also seen throughout the whole postnatal period. In pregnancies of Nos3-/- females, the average number of pups alive on D1 was significantly decreased compared to either E15 or E17. Placental histology revealed no abnormalities. On E15, E17, and D1, Nos3(-/-) fetuses demonstrated focal acute hemorrhages in the distal limbs in 0%, 2.6%, and 5.7%, respectively, of all mutant mice studied on the respective days. Bone measurements showed significantly shorter bones in the peripheral digits of hindpaws of Nos3-/- newborns. We conclude mice deficient for eNOS show characteristically abnormal prenatal and postnatal development including fetal growth restriction, reduced survival, and an increased rate of limb abnormalities. The development of this characteristic phenotype of eNOS-deficient mice dates back to the prenatal development during the late third trimester of pregnancy.