STAT4 and infection: Importantly, although CGRP activates the canonical CGRP receptor cAMP/PKA signaling pathway in LCs (16), we found that the anti-HIV-1 effects of CGRP in LCs are mediated via non-canonical NFκB/STAT4 signaling, as pharmacological inhibitors of both NFκB (13) and STAT4 (14) completely abrogate CGRP-induced inhibition of HIV-1 trans-infection.