Bile Acids Act as Soluble Host Restriction Factors Limiting Cytomegalovirus Replication in 1 Hepatocytes 2 Running title : Inhibitory Effects of Bile Acids on Cytomegalovirus 3

37 The liver constitutes a prime site of cytomegalovirus (CMV) replication and latency. Hepatocytes 38 produce, secrete and recycle a chemically diverse set of bile acids with the result that interactions 39 between bile acids and cytomegalovirus inevitably occur. Here we determined the impact of 40 naturally occurring bile acids on mouse CMV (MCMV) replication. In primary mouse 41 hepatocytes, physiological concentrations of taurochenodeoxycholic acid (TCDC) 42 glycochenodeoxycholic acid and to a lesser extent taurocholic acid significantly reduced MCMV43 induced gene expression and diminished the generation of virus progeny, while several other bile 44 acids did not exert antiviral effects. The anti-cytomegalovirus activity required active import of 45 bile acids via sodium-taurocholate cotransporting polypeptide (NTCP) and was consistently 46 observed in hepatocytes but not in fibroblasts. Under conditions in which IFN-α lacks antiviral 47 activity, physiological TCDC concentrations were similarly effective as interferon (IFN)-γ. A 48 detailed investigation of distinct steps of the viral life cycle revealed that TCDC deregulates viral 49 transcription and diminishes global translation in infected cells. 50