SARS-CoV-2 productively infects human brain microvascular endothelial cells.

BACKGROUND: The emergence of the novel, pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global health emergency. SARS-CoV-2 is highly contagious and has a high mortality rate in severe patients. However, there is very limited information on the effect of SARS-CoV-2 infection on the integrity of the blood-brain barrier (BBB). METHODS: RNA-sequencing profiling was performed to analyze the transcriptomic changes in human brain microvascular endothelial cells (hBMECs) after SARS-CoV-2 infection. Bioinformatic tools were used for differential analysis. Immunofluorescence, real-time quantitative PCR, and Western blotting analysis were used to explore biological phenotypes. RESULTS: A total of 927 differentially expressed genes were identified, 610 of which were significantly upregulated while the remaining 317 were downregulated. We verified the significant induction of cytokines, chemokines, and adhesion molecules in hBMECs by SARS-CoV-2, suggesting an activation of the vascular endothelium in brain. Moreover, we demonstrated that SARS-CoV-2 infection could increase the BBB permeability, by downregulating as well as remodeling the intercellular tight junction proteins. CONCLUSIONS: Our findings demonstrated that SARS-CoV-2 infection can cause BBB dysfunction, providing novel insights into the understanding of SARS-CoV-2 neuropathogenesis. Moreover, this finding shall constitute a new approach for future prevention and treatment of SARS-CoV-2-induced CNS infection.

Study on β-Chitosan against the binding of SARS-CoV-2S-RBD/ACE2 (preprint)

It has been known that SARS-CoV-2 which is considered similar to SARS-CoV invades human respiratory epithelial cells through interaction with the human angiotensin converting enzyme II (ACE2). In this work, SARS-CoV-2S-RBD and its cell receptor ACE2 were used to investigate the blocking effect and mechanism of {beta}-chitosan to the binding of them. Besides, inhibitory effect of {beta}-chitosan on inflammation induced by SARS-CoV-2S-RBD was also studied. Firstly, Native-PAGE results showed that {beta}-chitosan could bind with ACE2 or SARS-CoV-2S-RBD and the conjugate of {beta}-chitosan and ACE2 could no longer bind with SARS-CoV-2S-RBD. HPLC analyses suggested that was found the conjugate of {beta}-chitosan and SARS-CoV-2S-RBD displayed high binding affinity under the condition of high pressure (40 MPa) compared with that of ACE2 and SARS-CoV-2S-RBD. Furthermore, immunofluorescence detections on Vero E6 cells and hACE2 mice showed that {beta}-chitosan had a significant prevention and treatment effect on SARS-CoV-2S-RBD binding. Meanwhile, SARS-CoV-2S-RBD binding could activate the inflammation signaling pathways of cells and mice, however, {beta}-chitosan could dramatically suppress the inflammations activated by SARS-CoV-2S-RBD. Subsequently, Western blot analyses revealed that the expression levels of ACE2 in experimental groups treated with {beta}-chitosan significantly reduced. However, after the intervention of ADAM17 inhibitor (TAPI), the decreased ACE2 expressions affected by {beta}-chitosan up-regulated correspondingly. The results indicated that {beta}-chitosan has a similar antibody function, which can neutralize SARS-CoV-2S-RBD and effectively block the binding of SARS-CoV-2S-RBD with ACE2. ADAM17 activated by {beta}-chitosan can enhance the cleavage of ACE2 extracellular domain with a catalytic activity of Ang II degradation, and then the extracellular region was released into the extracellular environment. So, {beta}-chitosan could prevent the binding, internalization and degradation of ACE2 with SARS-CoV-2S-RBD and inhibit the activation of inflammatory signaling pathways at the same time. This work provides a valuable reference for the prevention and control of SARS-CoV-2 by {beta}-chitosan.