Figure 6

Figure 6

H3K18 lactylation affects neutrophil recruitment by increasing the levels of reactive oxygen species (a–c) Western blotting results showed that the levels of histone lactylation and histone lactation (H3K18) in zebrafish larvae after lactic acid treatment were significantly increased, and this lactate-induced upregulation was effectively inhibited when lactic acid was combined with metformin. (d,e) Q-PCR results showed that the levels of the pkma and gapdh genes related to lactic acid metabolism were significantly increased after lactic acid treatment, and this lactate-induced upregulation was effectively inhibited when lactic acid was combined with metformin. (f,g) Fluorescence staining results showing that lactic acid upregulated ROS levels in zebrafish. The addition of metformin alleviated the effect of hydrogen peroxide on reactive oxygen species in zebrafish (n = 25). (h,i) Q-PCR results showing that metformin treatment decreased the upregulation of dox and sod1 in lactate-induced zebrafish. (j,k,n,o) Pattern diagrams showing the caudal fin damage model and otic vesicle inflammation model generated from zebrafish infected with the Tg(lyz:EGFP) strain. Fluorescence images showing migrating neutrophils. The white rectangles indicate the counting area (scale bar: 200 μm). Lactic acid treatment significantly increased neutrophil recruitment to the injury site, and metformin mitigated this effect (n = 20). (l,m,p,q) Q-PCR results showing that metformin treatment decreased the upregulation of the inflammatory genes il-1β, il-6, cxcl8a, and tnf-α induced by lactic acid in juvenile zebrafish. (**** p  <  0.0001, *** p  <  0.001, ** p  <  0.01, * p  <  0.05, “ns”, no statistical difference).