TJP1 and infection: Verma et al. (2010) demonstrated that infection of HBCA astrocyte cell line with WNV upregulated the expression of MMP-1, -3, and -9 along with a downregulation of TIMP-2. Culture of microvascular endothelial cells with supernatants obtained from WNV-infected HBCA diminished the expression of claudin and ZO-1 and increased the permeability of in vitro BBB (Verma et al., 2010).