GPNMB promotes double-membrane vesicle accumulation and facilitates structural protein transport during PEDV infection.

Porcine epidemic diarrhea virus (PEDV) causes substantial economic losses in the swine industry globally. Host factors regulating the intracellular replication of PEDV, particularly early RNA synthesis and structural protein production, are not well understood, limiting antiviral strategies. We report that glycoprotein non‑metastatic melanoma protein B (GPNMB) is a key host factor promoting PEDV infection. Initially identified as a PEDV S1-binding partner, GPNMB was confirmed to enhance infection via loss-and gain-of-function experiments in Vero and IPEC-J2 cells. Genetic knockout of GPNMB inhibited PEDV replication without affecting viral attachment or internalization. We show that GPNMB is necessary for the accumulation of double-membrane vesicles (DMVs) and promotes early viral RNA synthesis. Notably, GPNMB directly interacts with the PEDV spike (S) and nucleocapsid (N) proteins, increases their abundance, and facilitates their transport from the endoplasmic reticulum (ER) to the Golgi apparatus, implicating it in structural protein maturation. Our work reveals a pivotal role for GPNMB in PEDV replication and nominates it as a target for host-directed antiviral intervention.