RT Journal Article SR Electronic T1 Streptococcus pneumoniae rapidly translocates from the nasopharynx through the cribriform plate to invade and inflame the dura JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.09.28.462246 DO 10.1101/2021.09.28.462246 A1 Teerawit Audshasai A1 Jonathan A. Coles A1 Stavros Panagiotou A1 Shadia Khandaker A1 Hannah E. Scales A1 Morten Kjos A1 Murielle Baltazar A1 Julie Vignau A1 James M. Brewer A1 Aras Kadioglu A1 Marie Yang YR 2021 UL http://biorxiv.org/content/early/2021/09/29/2021.09.28.462246.abstract AB The entry routes and translocation mechanisms of bacterial pathogens into the central nervous system remain obscure. We report here that Streptococcus pneumoniae (Sp) or polystyrene microspheres, applied to the nose of a mouse, appeared in the meninges of the dorsal cortex within minutes. Recovery of viable bacteria from dissected tissue and fluorescence microscopy showed that up to at least 72h, Sp and microspheres were predominantly in the outer of the two meninges, the pachymeninx. No Sp were found in blood or cerebrospinal fluid. Evidence that this was not an artifact of the method of administration is that in mice infected by horizontal transmission, Sp were also predominantly in the meninges and absent from blood. Intravital imaging through the skull, and flow cytometry showed recruitment and activation of LysM+ cells in the dorsal pachymeninx at 5h and 10h following intranasal infection. Imaging of the cribriform plate suggested that both Sp and microspheres entered through its foramina via an inward flow of fluid connecting the nose to the pachymeninx. Our findings bring further insight into the invasion mechanisms of bacterial pathogens such as Sp into the central nervous system, but are also pertinent to the delivery of drugs to the brain, and the entry of air-borne particles into the cranium.Competing Interest StatementThe authors have declared no competing interest.BHIBrain Heart InfusionCSFCerebrospinal FluidCSFECarboxyFluorescein Succinimidyl EsterCNSCentral Nervous SystemDCDendritic CellCFUColony Forming UnitGFPGreen Fluorescent ProteinFCSFetal Calf SerumIAVInfluenza A VirusLSMLaser Scanning MicroscopeN.A.Numerical AperturePBSphosphate buffered salinePFAparaformaldehydeSHGSecond Harmonic GenerationSpStreptococcus pneumoniae