Ginkgolide B alleviates oxidative stress and ferroptosis by inhibiting GPX4 ubiquitination to improve diabetic nephropathy.

ABSTRACT

Diabetic nephropathy (DN) is the leading cause of end­stage renal disease. Although Ginkgo biloba extract has a protective effect on DN, the protective effect and mechanism of its active ingredient Ginkgolide B (GB) on DN remain unclear. The aim of the present study was to investigate whether GB improves DN via alleviating oxidative stress and ferroptosis by inhibiting GPX4 ubiquitination in PA-G-induced mouse podocytes and DN mice. The study in vitro showed that GB effectively reduced serum total cholesterol, triglyceride concentrations and lipid accumulation in PA-G-induced MPC5 cells. In addition, GB promoted the expression of ferroptosis markers GPX4 and FTH1, while inhibited the expression of TfR1, fibrosis markers α-SMA and Collagen α1, as well as intracellular iron content and ROS levels. Interference of GPX4 expression with siRNA counteracted the effect of GB. And GB inhibited GPX4 ubiquitination in a dose-dependent manner. In vivo the experimental results showed that GB effectively reduced hyperglycemia, serum total cholesterol and triglyceride concentrations, reduced urinary albumin excretion and the number of renal lipid droplets, and improved changes in renal structure in DN mice. GB inhibited the expression of ferroptosis marker TfR1 and fibrosis markers α-SMA and Collagen α1, while promoted the expression of ferroptosis markers GPX4 and FTH1. In conclusion, the results suggested that GB may improve DN via protecting the kidney from ferroptosis and oxidative stress damage by inhibiting the ubiquitination of GPX4. These findings suggested that GB, a natural medicine, may be an effective therapeutic option for DN.