We then tested two independent methods in order to target microglia: (1) doxycycline treatment, which is known to attenuate microglia activation in the developing brain (Cunningham et al

We then tested two independent methods in order to target microglia: (1) doxycycline treatment, which is known to attenuate microglia activation in the developing brain (Cunningham et al., 2013) and (2) liposomes containing clodronate to deplete microglia by uptake and release into the cytosol of a non-hydrolysable ATP analog leading to cell death. and tested. The pathophysiology of congenital CMV disease is inherently complicated and involves different stages, from maternal CMV primary infection or reactivation and the associated maternal immune responses, to infection and dissemination within the developing brainnot to mention the crossing of the placental and blood-brain barriers. Insights into the early events following CMV infection of the developing brain are particularly needed. CMVs are generally species-specific; thus, the development of relevant animal models has been, and will continue to be, critical to our understanding of the mechanisms involved in CMV congenital brain disease (Britt et al., 2013; Cekinovic et al., 2014). Whereas multiple routes (intracranial, intraperitoneal or intraplacental) and developmental timepoints (antenatal or Imirestat neonatal) of CMV inoculation were used, and despite the lack of materno-fetal transmission of CMV infection in rodents, convergent insights into the alteration of innate and adaptive immune responses have emerged from such models (Kosmac et al., 2013; Sakao-Suzuki et al., 2014; Bradford et al., 2015; Slavuljica et al., 2015; Cloarec et al., 2016; Seleme et al., 2017). The production of cytokines by glial cells, the recruitment of peripheral immune cells, and the altered status of microglia, are all likely to influence neuropathogenesis. Microglia are targeted by CMV during human congenital disease (Teissier et al., 2014) and in murine models of intraplacental or neonatal infections (Kosugi et al., 2002; Sakao-Suzuki et al., 2014). Recently, we reported on a rat model of CMV infection of the developing brain displaying prominent infection of brain myelomonocytic cells and early alteration of microglia (Cloarec et al., 2016). Microglial cells originate from erythromyeloid progenitors Imirestat located in the yolk sac during embryogenesis (Ginhoux et al., 2010) and represent the resident mononuclear phagocytes of the brain (Ginhoux et al., 2013; Ginhoux and Jung, 2014). These cells play crucial roles not only in immune defense, maintenance of the neural environment, injury, and repair, but also in neurogenesis, synaptogenesis, synaptic pruning, connectivity, and modulation of synaptic and neuronal activity (Frost and Schafer, 2016). Importantly, early microglial responses might well combat against CMV infection; but these responses might likely have detrimental effects by interacting with important neurodevelopmental processes. To which extent and to which directionfavorable or detrimentalearly microglia alteration would influence the emergence and severity of neurodevelopmental phenotypes in the developing brain in the context of CMV infection represent an important pathophysiological question. Herein, we have tested whether early pharmacological targeting of microglia during pregnancy impacts postnatal neurological manifestations in our previously reported rat model of CMV infection of the embryonic brain (Cloarec et al., 2016) and have identified a critical role for microglia. Materials and methods Experimental design In this study, we explored whether neuroimmune events associated with brain CMV infection could be involved in the emergence of postnatal neurological consequences. We first explored whether infected rats would display phenotypes related to the human pathology. We then tested two independent methods in order to target microglia: (1) doxycycline treatment, which is known to attenuate microglia activation in Imirestat the developing brain (Cunningham et al., 2013) and (2) liposomes containing clodronate to deplete microglia by uptake and release into the cytosol of a non-hydrolysable ATP analog leading to cell death. Finally, we determined whether animals would still display postnatal neurological consequences following each treatment. Ethical statement Animal experimentations were performed in accordance with the French legislation and in compliance with the European Communities Council Directives (2010/63/UE). Depending on the age of the animals, euthanasia were performed after anesthesia with 4% isoflurane with overdose of pentobarbital (120 mg/kg) or with decapitation. This study was approved under the French department of agriculture and the local veterinary authorities by the Animal Experimentation Hdac11 Ethics Committee (n14 under licenses n01010.02 and n2016100715494790. CMV infection and pharmacological.