Fig. 6

SARS-CoV-2 damaged the integrity of BBB by downregulating and disorganizing TJ proteins. A RT-qPCR analysis of TJP1, OCLN, and CLDN5 transcription in hBMECs 24 and 72 h post-infection with SARS-CoV-2. RPL13A was used as the internal reference. Data were presented as the mean ± SD from three independent experiments. *p < 0.05, **p < 0.01. B Western blot analysis of TJP1, OCLN, and CLDN5 in hBMECs in response to SARS-CoV-2 at 24 and 72 h post-infection. β-Actin was used as the loading control, and differences were analyzed by densitometry. **p < 0.01, ***p < 0.001. C Immunofluorescence analyses of TJP1, OCLN, and CLDN5 expression and distribution in hBMECs 24 and 72 h after infection with SARS-CoV-2. Nuclei were stained in blue with DAPI, while TJP1, OCLN, and CLDN5 were stained in red. Scale bar, 10 μm. D Brain samples of both mice infected with SARS-CoV-2 for 5 d and those without were analyzed for the integrity of vascular endothelium by immunofluorescence. TJ proteins, TJP1, OCLN, and CLDN5 were selected as the markers reflecting the integrity of the vascular endothelium in red. CD31 was specifically applied for labeling the micro-vessels in green. The cell nucleus was stained in blue with DAPI. Scale bar indicates 50 μm