Mitochondrial respiratory chain regulates HBV clearance through dual modulation of lysosomal acidification

Mitochondria are vital for maintaining cellular homeostasis. However, mitochondrial damage is evident in patients with chronic hepatitis B (CHB). The role of mitochondrial dysfunction in the persistence of viral replication remains unclear. Therefore, this study aims to investigate the impact of mitochondrial dysfunction on HBV replication and elucidate the underlying mechanisms. Both mitochondria and lysosomes were dysfunctional in HBV-replicating cells. Moreover, HBV replication inhibited mitochondrial respiratory chain both in vitro and in vivo. Moderate inhibition of mitochondrial respiratory complex I activity using rotenone (Rot) increased HBV replication and decreased autophagic degradation capacity in vitro and in vivo. Mechanistically, elevated mitochondrial reactive oxygen species (mtROS) levels by Rot treatment or SOD2 knockdown led to deteriorated lysosomal membrane permeabilization, which elevated lysosomal pH and promoted HBV replication. Conversely, scavenging mtROS with mitoquinone (mitoQ) and mitoTEMPO (mitoT) had the opposite effect. Additionally, mitochondrial dysfunction reduced mitochondrial ATP production and diminished mitochondria-lysosome contacts. Obstructing mitochondrial ATP synthesis with Oligomycin A treatment or disruption of mitochondria-lysosome contacts with vacuolar protein sorting 13 A (VPS13A) knockdown resulted in lysosomal alkalinization and increased HBV replication by inhibiting vacuolar (H+)-adenosine triphosphatase (v-ATPase) assembly in an mtROS-independent manner. Ultimately, inhibition of mitochondrial complex I facilitated HBV secretion by promoting endosomal trafficking of HBV components. In conclusion, mitochondrial function plays a crucial role in HBV autophagic degradation. HBV impairs mitochondrial function, leading to a reduction in the lysosomal degradation capacity, which may hinder effective clearance of the virus.