Geniposide alleviates kidney fibrosis by targeting STAT3-HK2-mediated glycolysis.

Background: Geniposide (GP), which is extracted from the traditional Chinese herb Gardenia jasminoides, has extensive pharmacological effects. Recently, studies have shown its protective effects on kidney diseases. However, whether GP can alleviate unilateral ureteral obstruction (UUO)-induced renal interstitial fibrosis is unknown. In addition, its potential protective mechanism against kidney fibrosis is worthy of further study. We investigated the effect of GP on renal interstitial fibrosis induced by UUO in vivo and on HK-2 cells treated with transforming growth factor β1 (TGF-β1) in vitro and explored the underlying mechanisms involved.

Materials and methods: A UUO model was constructed, and the mice were treated with GP (50 mg/kg/day) for 10 days. The kidney injury score was used to evaluate the degree of kidney injury based on HE staining, and Masson staining and immunohistochemistry were used to evaluate kidney fibrosis. High-throughput sequencing analysis of animal samples was subsequently conducted, and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional and pathway enrichment analyses were subsequently performed to determine the possible mechanism, which were subsequently validated in vitro and in vivo. Western blotting was used to detect the signal transducer and activator of transcription 3 (STAT3)/hexokinase 2 (HK2) pathway, and molecular docking analysis was used to evaluate the binding ability of GP and STAT3. STAT3 was also overexpressed in HK-2 cells.

Results: GP alleviated renal fibrosis, regulated the glycolysis-related protein HK2 and inhibited glycolysis by binding to STAT3. In vitro experiments revealed that GP regulated glycolysis-related proteins and prevented cell epithelial-to-mesenchymal transition (EMT) during TGF-β1 treatment in HK-2 cells. Furthermore, the phosphorylation of STAT3 was drastically reduced in response to GP stimulation, leading to attenuated STAT3 nuclear translocation. Molecular docking analysis revealed a stable conformation between GP and STAT3 at Tyr705. The effects of GP were blocked by overexpression of STAT3.

Conclusion: Our results showed that GP protected against renal fibrosis, possibly through inhibiting STAT3/HK2 signaling-mediated glucose metabolism in UUO mouse kidneys.