Molecular mechanisms of Potentilla Discolor Bunge in regulating ferroptosis to alleviate DKD via the Nrf2 signaling pathway

Abstract

Ethnopharmacological relevance

Potentilla Discolor Bunge (PDB), a plant belonging to the Rosaceae family, is often used in traditional folk medicine to treat diabetes and prevent related complications. Additionally, fresh and tender PDB stems could be consumed as a vegetable or used to make tea.

Aim of the study

To explore the potential targets and mechanisms of PDB in treating Diabetic Kidney Disease (DKD) through network pharmacology, and to investigate its role in modulating the Nrf2 signaling pathway to inhibit ferroptosis using in vivo and in vitro experiments, thereby presenting a potential therapeutic avenue for DKD.

Materials and methods

Targets of PDB compounds were screened using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, while PDB action targets were screened using the DrugBank, OMIM, GeneCards, DisGeNET, and TTD databases. The intersecting targets were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Meanwhile, the binding modes of PDB core monomers to key targets were analyzed using Molecular Docking (MD) and Surface Plasmon Resonance (SPR) experiments. Experimental validation was conducted using a High-Fat/Sucrose Diet (HFD) combined with Streptozotocin (STZ)-induced DKD rat model and an Advanced Glycation End Products (AGEs)-damaged human renal proximal tubular cell (HK-2) model.

Results

As predicted through network pharmacology, PDB exerted therapeutic effects against DKD through multiple pathways, including AGE/RAGE, Nrf2 signaling, Oxidative Stress, and apoptosis. Furthermore, PDB's primary active constituents were Quercetin, Kaempferol, and β-sitosterol, with MD analyses suggesting strong binding affinities to the Nrf2 and Ho-1 proteins. In vivo experiments further revealed that PDB treatment reduced the 24 h urinary protein, Serum Creatinine (SCr), and urea levels. It also downregulated Malondialdehyde (MDA), Fe²⁺, and Reactive Oxygen Species (ROS) accumulation in renal tissues. Additionally, PDB alleviated the histopathological damage in DKD-afflicted rats and significantly upregulated Nrf2, Ho-1, Gpx4, and Slc7a11 in renal tissues. Moreover, Quercetin, Kaempferol, and β-sitosterol significantly upregulated Nrf2, Ho-1, and Gpx4, increased intracellular Glutathione (GSH) levels, reduced ROS and MDA content, and mitigated mitochondrial damage in the AGEs-exposed HK-2 cell injury model.

Conclusion

We predicted the mechanism of action of natural botanical PDB against DKD through network pharmacology, revealing that it significantly upregulated the Nrf2 signaling pathway and inhibited ferroptosis initiation, thus decelerating DKD progression. These findings were further validated through in vivo and in vitro experiments.