摘要
SARS-CoV-2 has been reported to show a capacity for invading the brains of humans and model animals.However,it remains undear whether and how SARS-CoV-2 crosses the blood-brain barrier(BBB).Herein,SARS-CoV-2 RNA was occasionally detected in the vascular wall and perivascular space,as well as in brain microvascular endothelial cells(BMECs)in the infected K18-hACE2 transgenic mice.Moreover,the permeability of the infected vessel was in creased.Furthermore,disin tegrity of BBB was discovered in the infected hamsters by administration of Evans blue.Interestingly,the expression of claudin5,ZO-1,occludin and the ultrastructure of tight junctions(TJs)showed unchanged,whereas,the basement membrane was disrupted in the infected animals.Using an in vitro BBB model that comprises primary BMECs with astrocytes,SARS-CoV-2 was found to infect and cross through the BMECs.Consistent with in vivo experiments,the expression of MMP9 was increased and collagen IV was decreased while the markers for TJs were not altered in the SARS-CoV-2-infected BMECs.Besides,inflammatory responses including vasculitis,glial activation,and upregulated inflammatory factors occurred after SARS-CoV-2 infection.Overall,our results provide evidence supporting that SARS-CoV-2 can cross the BBB in a transcellular pathway accompanied with basement membrane disrupted without obvious alteration of TJs.
基金
supported by the National Research and Development Project of China(2020YFC0841100)
National Natural Science Foundation of China(82061138007)
Fundamental Research Funds for CAMS of China(2020HY320001)
National Key Research and Development Project of China(2020YFA0707803)
CAMS initiative for Innovative Medicine of China(Grant No.2016-I2M-2-006).