MDSC-Derived Extracellular Vehicles Attenuate Renal Ischemia-Reperfusion Injury by Delivering miR-106b-5p to Target PDK4-Mediated Metabolic Reprogramming and Ferroptosis

Background: Ischemia-reperfusion injury (IRI) remains a major hurdle in kidney transplantation, particularly with expanded criteria donor (ECD) grafts. The initial ischemic insult triggers profound metabolic reprogramming in renal tubular epithelial cells (RTECs)—shifting from fatty acid oxidation (FAO) to glycolysis—disrupting energy homeostasis and promoting pathological lipid accumulation, which sensitizes cells to ferroptosis upon reperfusion. Current therapies largely target inflammation, overlooking this critical window of metabolic preconditioning. This study investigates whether MDSC-derived extracellular vesicles (MDSC-EVs) protect against renal IRI by transferring miR-106b-5p to RTECs, targeting PDK4 to reverse the glycolytic shift, restore FAO, and mitigate ferroptosis.
Methods: We will integrate clinical specimen analyses, murine kidney transplantation models, and in vitro hypoxia/reoxygenation assays to characterize the metabolic reprogramming landscape in IRI. The role of PDK4 will be dissected using renal tubule-specific PDK4 knockout mice and RTECs with genetic manipulation. Multi-omics (transcriptomics, metabolomics, single-cell sequencing) and molecular biology approaches (dual-luciferase reporter, Western blot, RT-qPCR) will be employed to validate the miR-106b-5p/PDK4 axis. Furthermore, the functional impact of this axis on ferroptosis will be examined through lipid peroxidation assays and mitochondrial morphology. Finally, a kidney-targeted, engineered MDSC-EV delivery system (LTH peptide-modified and thermosensitive hydrogel-encapsulated) will be developed and tested for its therapeutic efficacy and translational potential.
Results: This study demonstrate that MDSC-EVs ameliorate renal IRI by reversing the FAO-to-glycolysis switch and reducing lipid peroxidation. Mechanistically, miR-106b-5p delivered by MDSC-EVs will be shown to directly bind the 3’-UTR of PDK4 mRNA, downregulating its expression and thereby restoring pyruvate dehydrogenase activity, rebalancing glucose and fatty acid metabolism, and ultimately suppressing ferroptosis. The engineered kidney-targeted EVs are anticipated to enhance renal accumulation and prolong therapeutic effects in preclinical models.
Conclusion: MDSC-EVs, enriched with miR-106b-5p, target PDK4 in RTECs to reverse glycolipid metabolic reprogramming and alleviate renal ischemia-reperfusion injury via a non-inflammatory pathway. This reveals a non-canonical, metabolism-centric mechanism where the miR-106b-5p/PDK4 axis regulates metabolic flexibility and ferroptosis. The engineered exosome strategy thus offers a promising approach to mitigate IRI and improve kidney transplant outcomes.