Global Lactylome Reveals Lactylation-Dependent Mechanisms Underlying CXC Motif Chemokine Ligand 12 Expression in Pulmonary Endothelium During Acute Respiratory Distress Syndrome.

Acute respiratory distress syndrome (ARDS) is a life-threatening condition affecting millions of people worldwide. The severity of ARDS is associated with the dysfunction of pulmonary endothelial cells (PECs). Metabolic reprogramming is characterized by enhanced glycolysis and lactate accumulation, which play a critical role in this process. Here, we showed that lactate levels in the lungs of patients with ARDS were associated with disease severity and prognosis. Lactate promoted PEC dysfunction and drove experimental ARDS progression via lysine lactylation (Klac), a recently described posttranslational modification. Suppression of lactate-induced lactylation mitigated the development of ARDS and inhibited the release of chemokines, particularly CXC motif chemokine ligand 12 (CXCL12), from PECs. Through quantitative lactylome analysis, we identified hyperlactylation at K193 of Enolase 1 (Eno1), a glycolytic enzyme with RNA-binding capacity, as a previously unknown mechanism promoting CXCL12 production in PECs. Under homeostatic conditions, Eno1 could bind and inhibit the translation of CXCL12 mRNA, whereas increased glycolysis and accumulated lactate drove K193 hyperlactylation of Eno1 to release CXCL12 mRNA for accelerated translation. In addition, K193 hyperlactylation enhanced Eno1 enzymatic activity, further amplifying glycolysis. These findings establish Klac as a link between glycolytic reprogramming and PEC dysfunction, offering a new therapeutic target for ARDS.