Lactylation-driven ALKBH5 diminishes macrophage NLRP3 inflammasome activation in patients with G6PT deficiency.

BACKGROUND

Neutropenia represents an important clinical problem in patients with glycogen storage disease type Ib, characterized by genetic deficiency in glucose-6-phosphate translocase (G6PT/SLC37A4). However, the role of G6PT in macrophages has not been elucidated.

OBJECTIVE

We sought to investigate the function of G6PT in macrophage inflammation.

METHODS

Functional assays (including immunoblotting, real-time quantitative PCR, flow cytometry, immunofluorescence staining, and enzyme-linked immunosorbent assay) and RNA sequencing were performed.

RESULTS

We find that macrophages from patients deficient in G6PT exhibited diminished NLRP3 inflammasome activation. Mechanistically, deficiency of G6PT promotes glycolysis and lactate production in macrophages. Lactate accumulation potently induces ALKBH5 upregulation via H3K18 lactylation. ALKBH5 decreases m6A modification on NLRP3 messenger RNA, attenuating its transcript stability and thus inhibiting inflammasome activation. Further, treating G6PT-deficient macrophages with an inhibitor of the lactate dehydrogenase to lower their lactate levels restores NLRP3 inflammasome activation and rescues bacterial handling defect.

CONCLUSION

These findings reveal a previously unknown pathogenic mechanism of lactylation-driven defective NLRP3 inflammasome signaling and subsequent impaired antimicrobial activity as driving factors in these inflammatory disorders, indicating that glycolysis/lactate/histone lactylation cascade may be a potential therapeutic target for glycogen storage disease type Ib.