Exercise-induced circulating exosomes alleviate chemotherapy-induced peripheral neuropathy through PHLDA1 blockade in microglia

Chemotherapy-induced peripheral neuropathy (CIPN) lacks effective therapies and is linked to spinal microglial activation. Exercise alleviates CIPN in clinics, but the mediators and cellular targets remain unclear. To test whether exercise-induced circulating exosomes mitigate CIPN by delivering micro ribonucleic acids (microRNAs, miRNA) that suppress pleckstrin homology like domain family A member 1(PHLDA1) in spinal microglia and dampen nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)–driven neuroinflammation. Public CIPN transcriptomic datasets were integrated to nominate targets; PHLDA1 emerged as a convergent hit and was mapped across neural cell types using the Human Protein Atlas and single-cell resources. A cisplatin CIPN model was established in C57BL/6J mice with behavioral endpoints (von Frey, adhesive removal). Voluntary wheel running served as the exercise intervention. Serum exosomes from exercised or sedentary mice (Exercise-derived Exosomes[Exo-E]/ Non-exercise Exosome Control [Exo-NC]) were isolated by differential ultracentrifugation and characterized by transmission electron microscopy (TEM)/ scanning electron microscopy (SEM), nanoflow cytometry (CD9/CD63/CD81), and nanoparticle tracking analysis (NTA). Exosome trafficking was assessed by PKH67/DiR tracing in vitro and in vivo. Small-RNA sequencing of human exercise exosomes was integrated with a bovine exercise dataset to identify conserved miRNAs. BV2 and primary microglia assays quantified PHLDA1, NF-κB signaling (phosphorylated IκB kinase β[p-IKKβ], phosphorylated NF-κB p65[p-p65], inhibitor of nuclear factor kappa B alpha [IκBα]), and cytokines (enzyme-linked immunosorbent assay [ELISA]/ quantitative polymerase chain reaction [qPCR]). Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) knockout tested PHLDA1 necessity. PHLDA1 was upregulated in CIPN datasets and from dorsal horn tissue from cisplatin-treated mice alongside elevated microglial inducible nitric oxide synthase (iNOS) and pro-inflammatory transcripts. Exercise reversed mechanical hypersensitivity and shortened adhesive-removal latency, while lowering spinal PHLDA1 and inflammatory markers. Exo-E displayed canonical vesicle markers, crossed the blood–brain barrier and entered microglia. Cross-species miRNA profiling identified miR-122-5p, miR-181b-5p, and miR-485-5p as exercise-induced candidates predicted to target PHLDA1; the levels of these miRNAs increased in microglia after Exo-E treatment. Exo-E, but not Exo-NC, reduced PHLDA1, suppressed NF-κB activation, and decreased tumor necrosis factor alpha (TNF-α)/ Interleukin 6(IL-6) in LPS- or drug-challenged microglia. PHLDA1 knockout phenocopied Exo-E’s anti-inflammatory effects. Voluntary exercise alleviates CIPN by delivering serum exosomal miRNAs that downregulate PHLDA1 in spinal microglia, blunting NF-κB–mediated neuroinflammation. Targeting the exercise-exosome–miRNA–PHLDA1 axis represents a translational strategy to prevent or treat CIPN. Exercise-induced circulating exosomes mimic the analgesic benefits of exercise to relieve chemotherapy-induced peripheral neuropathy (CIPN) by silencing microglial PHLDA1 and dampening NF-κB signaling.