Alanyl-Transfer RNA Synthetase 1 and Cyst Growth in Autosomal Dominant Polycystic Kidney Disease

Alanyl-transfer RNA synthetase 1 (AARS1) was upregulated and promoted cyst growth in autosomal dominant polycystic kidney disease. AARS1 promoted lysine lactylation of signal transducer and activator of transcription 3 (K140) and NF-κB p65 (K310), enhancing their phosphorylation, interaction, and transcriptional activity. AARS1 transcriptionally repressed its novel targets, Atg5 and Dusp4, to impair autophagy but activate polycystic kidney disease signaling pathways.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disorder, characterized by metabolic reprogramming with enhanced glycolysis and lactate accumulation. However, the enzyme that senses lactate and uses it as a substrate for protein lactylation in ADPKD remains unknown. Alanyl-transfer RNA synthetase 1 (AARS1) is a lactate-responsive enzyme with lactyltransferase activity, while its role and mechanisms in ADPKD have not been defined.

To investigate the role of AARS1, we generated Pkd1 and Aars1 double conditional knockout Pkd1fl/fl:Aars1fl/fl:Ksp-Cre mice and evaluated the effect of AARS1 inhibitor β -alanine in two ADPKD mouse models. Coimmunoprecipitation and Cleavage Under Targets and Tagmentation analyses were performed to identify novel AARS1 substrates and downstream target genes involved in cystogenesis.

AARS1 was elevated in Pkd1 mutant renal epithelial cells and kidneys, and genetic deletion of Aars1 significantly delayed cyst growth, preserved kidney function, and reduced renal lactylation in Pkd1 mutant mice. Mechanistically, AARS1 promoted lactylation-dependent activation of signal transducer and activator of transcription 3 (STAT3) and NF-κB (p65), specifically at STAT3 K140 and p65 K310, thereby amplifying pro-proliferative and proinflammatory transcriptional programs. AARS1 also associated with promoter regions and mediated histone H3 lysine 14 lactylation, thereby repressing the transcription of Atg5 to impair autophagy and suppressing the transcription of Dusp4 to sustain phosphorylation of cAMP response element-binding protein and retinoblastoma protein. Cytokine signaling through IL-6 and TNF- α further reinforced AARS1 expression through STAT3- and NF-κB-dependent feed-forward loops. Importantly, inhibition of AARS1 with β -alanine markedly slowed cyst progression in Pkd1 mutant mouse models.

Our study identified AARS1 as a central metabolic sensor linking lactate-driven lysine lactylation to transcriptional, epigenetic, and signaling pathways that drive ADPKD progression.