Acetylation of Hint2 mitigates acute liver failure by suppressing neutrophil chemotaxis and NETosis through maintaining mitochondrial calcium and protein homeostasis

Background: Acute liver failure (ALF) is a life-threatening condition marked by high mortality, poor prognosis, and limited treatment options. Excessive neutrophil infiltration and NETosis are key drivers of hepatic inflammation and injury, yet the underlying molecular mechanisms remain unclear. This study identifies histidine triad nucleotide-binding protein 2 (Hint2) as a pivotal regulator of neutrophil chemotaxis and NETosis during ALF.

Methods: Hint2 overexpression (OE), lysine 119 mutant (K119R), and knockdown (Sh) mice were generated via lentiviral transduction and subjected to LPS/D-Gal-induced ALF. Liver injury and neutrophil infiltration were assessed by histology, immunofluorescence, serum NETs quantification, and flow cytometry. In vitro, lentiviral-mediated Hint2 modulation was performed in neutrophil-like differentiated HL-60 cells and murine bone marrow-derived neutrophils to examine mitochondrial CA²⁺ homeostasis, proteostasis, and chemotaxis using transwell assays and in vivo imaging.

Results: Hint2 OE mice showed reduced hepatic neutrophil recruitment, diminished NETosis, and attenuated liver injury during ALF, whereas Hint2 Sh exacerbated these effects. Pharmacological HDAC6 inhibition with ACY1215 restored Hint2 acetylation and activity, mitigating neutrophil-driven liver damage. The K119R mutation suppressed Hint2 activity, and promoted neutrophil migration and NETosis, aggravating hepatic injury.

Conclusion: Acetylation of Hint2 at K119 preserves mitochondrial calcium and protein homeostasis, thereby limiting neutrophil chemotaxis and NETosis in ALF. Targeting Hint2 acetylation represents a promising therapeutic strategy to mitigate neutrophil-driven liver injury.

ALF; Acetylation; HDAC6; Hint2; Mitochondria; NETosis.