Porcine reproductive and respiratory syndrome virus activates the pentose phosphate pathway via the ROS/HIF-1α/G6PD axis to promote viral replication.

Porcine reproductive and respiratory syndrome virus (PRRSV), a highly contagious pathogen in swine, poses significant economic challenges to global pork production. This study elucidated the regulatory interplay between PRRSV infection and the pentose phosphate pathway (PPP), a critical metabolic axis for anabolism. Comparative metabolomic profiling of porcine alveolar macrophages (PAMs) pre- and post-PRRSV infection demonstrated marked upregulation of PPP activity, concomitant with elevated levels of nucleotide biosynthesis. This metabolic shift was driven by PRRSV-induced upregulation of glucose-6-phosphate dehydrogenase (G6PD), the PPP's rate-limiting enzyme. Mechanistic investigations revealed that PRRSV infection stimulated hypoxia-inducible factor 1α (HIF-1α) expression, which transcriptionally activates G6PD. Genetic silencing of HIF-1α abolished PRRSV-mediated G6PD induction. Furthermore, reactive oxygen species (ROS) accumulation was identified as the upstream regulator of HIF-1α activation during PRRSV infection. Pharmacological ROS scavenging disrupted the ROS/HIF-1α/G6PD signaling cascade, diminished NADPH and reduced glutathione production, and consequently attenuated viral proliferation. These results established that PRRSV exploited the ROS/HIF-1α axis to reprogram host glucose metabolism through PPP potentiation, creating a biosynthetic environment conducive to viral propagation.