Supplementary Material for: DOT1L regulates cellular senescence during the progression from acute kidney injury to chronic kidney disease via the micro-222-5p/WNT9B signaling pathway.

Background: Acute kidney injury (AKI) is a common clinical condition where cellular senescence plays a crucial role in its progression. Previous studies have suggested that DOT1L plays a pivotal role in cellular senescence, yet its specific mechanisms in regulating AKI cellular senescence remain unclear.
Methods: This study utilized a glycerol-induced in vivo AKI model and employed the DOT1L-specific inhibitor EPZ004777 (EPZ) to suppress DOT1L function. Aging staining, PAS staining, and Masson staining were employed to assess renal aging, injury, and interstitial fibrosis. In vitro experiments utilized doxorubicin-treated human kidney tubular epithelial (HK-2) cells to establish an AKI cellular senescence model. EPZ was used to inhibit DOT1L, evaluating its impact on cellular senescence. High-throughput miRNA sequencing was performed to analyze differential expression of miRNAs downstream of DOT1L, and DOT1L overexpression and dual luciferase reporter gene experiments were conducted to explore interactions among DOT1L, miR-222-5p, and WNT9B.
Results: The results demonstrated that in vivo inhibition of DOT1L significantly reduced cellular senescence and improved renal tubular injury and interstitial fibrosis. In the doxorubicin -induced HK-2 cell model, DOT1L inhibition markedly decreased cellular senescence and lowered mRNA and protein levels of senescence markers, while alleviating cell cycle arrest. DOT1L inhibition notably upregulated miR-222-5p expression and suppressed WNT9B expression, with opposite effects observed with DOT1L overexpression.
Conclusion: DOT1L regulates cellular senescence through the miR-222-5p/WNT9B pathway in AKI. These findings suggest that DOT1L may serve as a potential therapeutic target to mitigate the progression of AKI to chronic kidney disease.