Microtubule depolymerization limits porcine betacoronavirus PHEV replication

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a typical neurotropic betacoronavirus causing digestive disease and/or neurological dysfunction in neonatal pigs. Actin filaments have been identified to implicate in PHEV invasion, but the effects of viral infection on microtubules (MTs) cytoskeleton are unknown. Here, we observed that PHEV infection induced MT depolymerization and was accompanied by the disappearance of microtubule organizing centers. Depolymerization of MTs induced by nocodazole significantly inhibited viral RNA replication, but over-polymerization of MTs induced by paclitaxel did not substantially affect PHEV infection. The expression of histone deacetylase 6 (HDAC6), an important regulator of MT acetylation, progressively increased during PHEV infection. Tramstatin A could alter HDAC6 deacetylase activity to enhance the acetylation of the substrate α-tubulin and MT polymerization, but does not increase PHEV proliferation. These findings suggest that PHEV could subvert host MT cytoskeleton to facilitate infection, and that MT depolymerization negatively affects viral replication independently of HDAC6 activity.