Organotypic Brain Cultures: A Framework for Studying CNS Infection by Neurotropic Viruses and Screening Antiviral Drugs

According to the World Health Organization (WHO), at least 50% of emerging viruses endowed with pathogenicity in humans can infect the Central Nervous System (CNS) with induction of encephalitis and other neurologic diseases ( Taylor et al., 2001 ; Olival and Daszak, 2005). While neurological diseases are progressively documented, the underlying cellular and molecular mechanisms involved in virus infection and dissemination within the CNS are still poorly understood (Swanson and McGavern, 2015; Ludlow et al., 2016 ). For example, measles virus (MeV) can infect neural cells, and cause a persistent brain infections leading to lethal encephalitis from several months to years after primary infection with no available treatment (Reuter and Schneider-Schaulies, 2010; Laksono et al., 2016 ). The Organotypic Brain Culture (OBC) is a suitable model for the virology field to better understand the CNS infections. Indeed, it allows not only studying the infection and the dissemination of neurotropic viruses within the CNS but it could also serve as screening model of innovative antiviral strategies or molecules, such as our recently published studies about fusion inhibitory peptides and the HSP90 chaperone activity inhibitor, 17-DMAG ( Welsch et al., 2013 ; Bloyet et al., 2016 ). Based on our previous work, we propose here an optimized method to prepare OBC of hippocampi and cerebellums which are suitable for small rodent models based virus studies, including mice, rats as well as hamsters at a post-natal stage, between P6 to P10. We notably took into account the stress of the slice procedure on the tissue and the subsequent cellular reactions, which is essential to fully characterize the model prior to any use in infectious conditions. With this knowledge, we propose a protocol highlighting the requirements, including potential trouble shootings of the slicing parameters, to consider the variations we observed according to the structure and animal studied. This framework should facilitate the use of OBC for better conclusive studies of neurotropic viruses.