1. NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin 300134, China
2. Tianjin Medical University General Hospital Airport Hospital, Tianjin 300308
3. Department of Endocrinology and Metabolism, the Third Central Hospital of Tianjin, 83 Jintang Road, Hedong District, Tianjin 300170, China.
*Yun-hong Lu and Yun-peng Chang contributed equally to this study.
Hyperuricemia (HUA) is a metabolic disease characterized by elevated serum uric acid (SUA). Empagliflozin, a kind of sodium-glucose cotransporter 2 inhibitors, has recently emerged as a new antidiabetic agent by facilitating glucose excretion in urine. Moreover, there was evidence of SUA reduction following treatment with empagliflozin in addition to glycaemic control, while the molecular mechanisms remain unknown. To investigate the potential mechanisms, the model of type 2 diabetes (T2DM) with HUA was established by combination of peritoneal injection of potassium oxonate and intragastric administration of hypoxanthine in KK-Ay mice. A series of method such as RT-PCR, western blot, immunochemistry, immunofluorescence were conducted to explore the mechanism. Our results showed that empagliflozin significantly ameliorated the levels of SUA and blood glucose in T2DM mice with HUA. Furthermore, in both kidney and ileum, empagliflozin obviously promoted protein expression of uric acid (UA) transporter ABCG2, p-AMPK, p-AKT and p-CREB. The same trend was observed in human tubular epithelial (HK-2) cells. Additionally, through application of an AMPK inhibitor (Compound C), it was further confirmed empagliflozin exerted its anti-hyperuricemic effects in an AMPK dependent manner. Meanwhile, with the help of ChIP assay and luciferase reporter gene assay, we found that CREB further activated ABCG2 via binding to the promoter of ABCG2 to induce transcription. Taken together, our study demonstrated that empagliflozin treatment played an essential role in attenuating HUA by upregulation of ABCG2 via AMPK/AKT/CREB signaling pathway.
Keywords: hyperuricemia, SGLT2, AMPK, empagliflozin, ABCG2, CREB