PDK4-dependent lactate production and lactylation promote renal calcium oxalate crystal-induced EMT and mitochondrial dysfunction via the TGF-β/SMAD3/GPX4 axis

  • Cell Signal. 2026 Jun 27:147:112701. doi: 10.1016/j.cellsig.2026.112701.
Boming Zhang  1 ,  Kai Liu  2 ,  Ruixin Fan  3 ,  Youmiao Zeng  3 ,  Heng Li  4
Affiliations
  • 1. Department of Urology, Tongji Hospital of Tongji Medical College, Hubei Provincial Clinical Medical Research Center for Minimally Invasive Treatment of Urology, Huazhong University of Science and Technology, Wuhan, Hubei 430011, China.
  • 2. Department of Urology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong 250000, China; Shandong Medicine and Health Key Laboratory of Organ Transplantation and Nephrosis, Shandong Institute of Nephrology, Jinan, Shandong 250000, China.
  • 3. Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, China.
  • 4. Department of Urology, Tongji Hospital of Tongji Medical College, Hubei Provincial Clinical Medical Research Center for Minimally Invasive Treatment of Urology, Huazhong University of Science and Technology, Wuhan, Hubei 430011, China. Electronic address: [email protected].
PMID: 42364861 DOI: 10.1016/j.cellsig.2026.112701
Abstract

Background: Urolithiasis is a highly prevalent urinary system disease imposing a significant global health burden, with calcium oxalate (CaOx) stones constituting the majority of cases. The underlying metabolic and epigenetic mechanisms driving CaOx stone formation remain incompletely understood.

Methods: Through integrated single-cell, spatial, and bulk transcriptomic analyses, this study identified PDK4 as a key gene upregulated by CaOx stones in renal proximal tubular epithelial cells (PTECs). In vitro and in vivo models of CaOx stones were established using calcium oxalate monohydrate (COM) treatment and glyoxylic acid (Gly) induction, respectively. Genetic and pharmacological inhibition of PDK4, knockdown of Lactate Dehydrogenase a (LDHA), and TGF-β inhibitor SB-431542 intervention were employed. Assays for lactate measurement, protein lactylation, epithelial-mesenchymal transition (EMT) markers, mitochondrial function, chromatin immunoprecipitation (ChIP)-qPCR for SMAD3 binding to the GPX4 promoter, and signaling pathway components (TGF-β/SMAD3/GPX4) were performed.

Results: CaOx stones upregulated PDK4 expression in PTECs, leading to glycolytic dysfunction and lactate accumulation. Elevated lactate drove protein lactylation, which subsequently activated the TGF-β/SMAD3 signaling and enhanced SMAD3 binding to the GPX4 promoter to repress GPX4 transcription. This cascade ultimately exacerbated CaOx stone-induced epithelial-mesenchymal transition (EMT) and mitochondrial dysfunction in PTECs. Conversely, pharmacological inhibition of TGF-β signaling alleviated CaOx stone-induced renal injury, EMT, and mitochondrial dysfunction in vivo. Inhibition of PDK4 or reduction of lactate production blocked this axis and attenuated the pathological processes.

Conclusion: These findings delineate a novel PDK4/lactate/lactylation/TGF-β/SMAD3/GPX4 metabolic-epigenetic regulatory axis in CaOx stone-induced renal injury. This pathway provides new mechanistic insights and identifies potential therapeutic targets for nephrolithiasis.

Keywords
Calcium oxalate stone; Epithelial-mesenchymal transition; Lactate; Lactylation; Mitochondrial dysfunction; PDK4; TGF-β signaling pathway.
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