Swine acute diarrhea syndrome coronavirus (SADS-CoV) is a recently discovered enteric coronavirus that has caused considerable economic losses in the pig industry. SADS-CoV was first reported in 2017 in Guangdong Province, China, and subsequently in Fujian, Guangxi, Henan and Jiangxi Provinces. Bone marrow stromal cell antigen 2 (BST-2), also known as tetherin, acts as an antiviral protein to limit the release of a wide range of enveloped viruses. However, the relationship between BST-2 and SADS-CoV has rarely been studied. Here, we showed that endogenous BST-2 expression is downregulated by SADS-CoV infection in Vero-E6 and ST cells by 2- to 3-fold. The overexpression of BST-2 inhibited SADS-CoV replication, whereas the knockdown of the BST-2 gene in Vero cells restored SADS-CoV replication. Further study revealed that BST-2 targets the SADS-CoV nucleocapsid protein (N) and decreases N protein expression, and that the BST-2 transmembrane (TM) domain is essential for this activity. Moreover, the degradation of the SADS-CoV N protein promoted by BST-2 is mediated by the membrane-associated ring-CH-type finger 8 (MARCHF8)/calcium binding and coiled-coil domain 2 (NDP52) autophagosome pathway. Overall, we found that BST-2 suppresses viral proliferation by inducing the breakdown of the SADS-CoV N protein via the MARCHF8/NDP52 pathway.
Baicalein is the main active compound of Scutellaria baicalensis Georgi, a medicinal herb with multiple pharmacological activities, including the broad anti-virus effects. In this paper, the preclinical study of baicalein on the treatment of COVID-19 was performed. Results showed that baicalein inhibited cell damage induced by SARS-CoV-2 and improved the morphology of Vero E6 cells at a concentration of 0.1 μM and above. The effective concentration could be reached after oral administration of 200 mg/kg crystal form β of baicalein in rats. Furthermore, baicalein significantly inhibited the body weight loss, the replication of the virus, and relieved the lesions of lung tissue in hACE2 transgenic mice infected with SARS-CoV-2. In LPS-induced acute lung injury of mice, baicalein improved the respiratory function, inhibited inflammatory cell infiltration in the lung, and decreased the levels of IL-1β and TNF-α in serum. In conclusion, oral administration of crystal form β of baicalein could reach its effective concentration against SARS-CoV-2. Baicalein could inhibit SARS-CoV-2-induced injury both in vitro and in vivo. Therefore, baicalein might be a promising therapeutic drug for the treatment of COVID-19.
危险品化学品经营许可证（带存储）