MMP9 and infection: Moreover, RECK regulates MMP9 and exerts its effects primarily through suppression of WNT7A/WNT7B (Cho et al., 2017), but regulation of neither Wnt7a nor Wnt7b regulation was observed in our gene microarray dataset, and scRNA-Seq did not detect Wnt7a nor Wnt7b expression, before or after infection, in any ME cells.