Twist Family BHLH Transcription Factor 1 orchestrates hypoxia-lactate crosstalk to bridge glycolytic flux and tubular maladaptation in fibrotic kidneys.

The reprogramming of glycolytic metabolism is essential for maintaining the reparative homeostasis of tubular epithelial cells (TECs). Maladaptive TEC repair mechanisms drive the progression from acute kidney injury (AKI) to chronic kidney disease (CKD). Twist Family BHLH Transcription Factor 1 (Twist1) has been implicated in epithelial-mesenchymal transition and metabolic dysregulation in cancer and fibrotic diseases. Twist1 promotes renal fibrosis through lipid accumulation in TECs by transcriptionally regulating genes involved in lipid metabolism. The role of Twist1 in glycolytic reprogramming during the transition from AKI to CKD was investigated. Tubular Twist1 knockout mice, RNA sequencing, metabolomics, and in vivo and in vitro experiments were used to evaluate the function and mechanism of Twist1-regulated glycolytic reprogramming. Twist1 orchestrated a dual metabolic insult of fatty acid oxidation suppression and glycolysis hyper-activation, thereby rewiring TEC processes toward a pro-fibrotic phenotype. Hypoxia-induced Twist1 activated hexokinase-2-driven glycolysis and amplified lactate accumulation, thereby stabilizing Twist1 expression through epigenetic modifications. Multidimensional studies demonstrated that lactate significantly enhanced maladaptive repair processes in TECs and contributed to renal fibrosis through a positive feedback loop that exacerbated glycolysis. Mechanistically, lactylation of histone H3 at K18 (H3K18lac) upregulated Twist1 transcription, which in turn accelerated hexokinase-2 expression and further promoted glycolytic activity. This study elucidates a lactate/H3K18lac/Twist1/hexokinase-2 axis as a central mechanism driving AKI-to-CKD progression. Twist1 emerges as a hypoxia-responsive transcription factor that amplifies glycolysis in a self-reinforcing cycle that fuels fibrosis. This study uniquely positions Twist1 as a hypoxia-responsive transcription factor in renal fibrosis and implicates lactate in autocrine TEC reprogramming.