USP10 regulates SLC7A11/PFBFB3/TFAP2C axis to inhibit the ferroptosis of allotransplanted islet β cells
Yi Wang1,2, Hailian Wang2, Xiaobo Huang1, Leo H Buhler2,3.
1Center for Critical Care Medicine, Sichuan Academy of Medical Sciences and Sichuan People's Hospital, Chengdu, People's Republic of China; 2Institute of Organ Transplantation, Sichuan Academy of Medical Sciences and Sichuan People's Hospital, Chengdu, People's Republic of China; 3Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
Objective: Islet transplantation is an effective treatment for type 1 diabetes mellitus by regulating blood glucose levels. However, the long-term survival of allogeneic transplanted islets is quite poor. Previous studies have demonstrated that the inhibition of ferroptosis could prolong the survival of transplanted islets in vivo. However, the underlying mechanisms for allogenic transplanted islet ferroptosis are still unclear. Therefore, unraveling the mechanisms will provide a novel strategy for prolonging the transplanted islets.
Methods: By utilizing conditional gene knockout mice and allogeneic islet transplantation models, we aim to study the de-ubiquitin mechanism of USP10 on SLC7A11. Meanwhile, we performed gene editing, adenovirus transfection, and ubiquitination assay. Furthermore, we investigated the regulatory mechanism of the SLC7A11/PFKFB3/TFAP2C axis on ferroptosis of allogeneic transplant islet β cells through co-immunoprecipitation, chromosomal immunoprecipitation sequencing and ferroptosis detection.
Results: Within one month of allogenic islet transplantation, the islets undergo ferroptosis. By ubiquitination assay, we observed the key ferroptosis regulator as SLC7A11 undergo degradation by ubiquinase. However, the deubiquitinase enzyme USP10 can remove the ubiquitin of SLC7A11 by in vitro and in vivo ubiquitination assay. Further, SLC7A11 can promote the nucleus translocation of glycolytic enzyme PFKFB3, the binding of nucleus PFKFB3 to the transcription factor TFAP2C by co-immunoprecipitation. By chromosomal immunoprecipitation sequencing and chromosomal immunoprecipitation PCR, we observed that the PFKFB3/TFAP2C complex binds at the promoter region of Gpx4, and thereby stimulates the transcription of Gpx4. Ablation of USP10 led to increased SLC7A11 degradation, decreased nucleus PFKFB3, less GPX4 in the cytoplasm, and increased ferroptosis in the allogenic transplanted isle.
Conclusion: Our study indicates that overexpression of USP10 by AAV could inhibit ferroptosis of allogenic transplanted islets via SLC7A11/PFKFB3/TFAP2C axis. Therefore, our study provides novel ideas and therapeutic targets for prolonging the long-term survival of pancreatic islet transplantation.
