GPR4 and Arthritis: While the anti-inflammatory effects of GPR4 antagonists have been shown in other models of inflammatory diseases, such as arthritis and colitis (Dong et al., 2013; Dong et al., 2017; Sanderlin et al., 2019; Tobo et al., 2015; Velcicky et al., 2017; Miltz et al., 2017; Krewson et al., 2020), the anti-viral effects were first uncovered in this study.