TRIM22 promotes K48-linked ubiquitination of LDHA, leading to the inhibition of HBV replication

Chronic hepatitis B (CHB) remains a major global public health challenge. Tripartite motif-containing protein 22 (TRIM22) is an interferon-stimulated gene, but whether its E3 ubiquitin ligase activity is involved in regulating HBV replication remains unclear. Accumulating evidence indicates that lactate dehydrogenase A (LDHA) promotes HBV replication, and LDHA inhibition represents a promising host-directed antiviral strategy for HBV therapy. Serum samples from 208 CHB patients were collected to analyze the correlation between lactate dehydrogenase (LDH) levels and clinical parameters. The GSE65359 dataset was used, and TRIM22-overexpressing cell models were established. The association between TRIM22 and glycolysis was assessed by transcriptomic sequencing, targeted metabolomics and Seahorse extracellular acidification rate (ECAR) analysis. TRIM22-interacting proteins were screened by co-immunoprecipitation coupled with LC-MS/MS and validated. TRIM22 domain-deletion mutants were constructed and together with MG132 treatment, were used to verify the ubiquitin-proteasome degradation of LDHA, as well as the effects of the mutations on the RIG-I-MAVS pathway and HBV markers. Functional rescue experiments were performed via LDHA co-transfection and Amlexanox treatment. Additionally, LDHA overexpression was used to assess its downstream effects. Clinical analysis revealed that serum LDH levels positively correlated with both HBV viral load and liver injury markers. Public database analysis showed that TRIM22 was negatively correlated with LDHA and lactate transporters in CHB liver tissues. TRIM22 overexpression attenuated glycolysis and activated the TCA cycle. ECAR analysis confirmed that TRIM22 overexpression suppressed glycolytic flux. LDHA was identified as a novel interacting protein of TRIM22. Further experiments confirmed that TRIM22 binds LDHA through its coiled-coil domain and promotes its K48-linked ubiquitination via its RING domain. This degradation inhibited HBV replication and enhanced activation of the Retinoic-acid-inducible gene I (RIG-I) - Mitochondrial antiviral signaling protein (MAVS) pathway. Transcriptomic and functional studies further demonstrated that LDHA overexpression promoted HBV replication by suppressing the RIG-I-MAVS pathway, potentially through downregulation of C-C motif chemokine ligand 3 like 1 (CCL3L1) and C-C motif chemokine ligand 24 (CCL24). Our findings define a novel mechanism by which TRIM22 ubiquitinates LDHA through its RING domain, thereby inhibiting the glycolytic pathway and activating the RIG-I-MAVS pathway, consequently suppressing HBV replication. This provides a potential foundation for developing new therapeutic strategies against HBV.