Crocin alleviates renal fibrosis through inhibiting mitochondrial dysfunction via regulating HOXD8/PGC‑1α pathways

Crocin, a key bioactive compound derived from saffron ( Crocus sativus L .), a traditional Chinese medicinal and edible herb, exhibits renoprotective effects against fibrosis, but the mechanisms remain unclear. Here we show that homeobox D8 (HOXD8) and PGC1-α are downregulated, while reactive oxygen species levels, mitochondrial dysfunction, and fibrosis are increased in kidney fibrosis models. HOXD8 overexpression increases PGC1-α expression, reduces reactive oxygen species, restores mitochondrial function, and suppresses profibrotic genes. Crocin upregulates HOXD8 and mitigates mitochondrial dysfunction and fibrosis. Mechanistically, HOXD8 binds the PGC1-α promoter and enhances its transcription. DNMT1-mediated promoter hypermethylation drives HOXD8 downregulation, and crocin reduces DNMT1 enrichment and activity at this promoter. Molecular docking and cellular thermal shift assay support a potential interaction between crocin and HOXD8, and crocin reduces HOXD8 ubiquitination. These findings suggest that crocin upregulates HOXD8 by inhibiting both its promoter hypermethylation and protein ubiquitination, thereby ameliorating mitochondrial dysfunction and fibrosis in chronic kidney disease (CKD).