DDIT4 mediated autophagy and ferroptosis through VDR-mTOR signaling pathway in the treatment of diabetic kidney disease

Abstract To determine the changes in the expression of DNA damage inducing transcription factor 4 (DDIT4) and the gene related to the activation of vitamin D receptor (VDR) in diabetic kidney disease (DKD) patients and experimental mice, and to explore the molecular mechanism of DDIT4 in the treatment of DKD. The pathological damage of kidney tissue and the molecular expression of VDR-mTOR related pathway in DKD patients and db/db mouse models were observed by periodate schiff (PAS) staining and immunohistochemistry (IHC) staining; furthermore, diabetic cell models were established in mouse immortalized kidney podocyte line MPC5 cells and mouse glomerular mesangial cell line SV40-MES-13 cells by high glucose culture, transfected with DDIT4 plasmid, observed cell morphological changes by transmission electron microscopy and laser confocal microscopy, and detected VDR/mTOR/p70s6k/4E-BP1 signal pathway protein expression by qRT-PCR and western blotting. PAS staining and IHC staining results showed that pathological damage of kidney tissue was observed in samples of DKD patients and in db/db mouse models. The results of qRT-PCR and western blotting showed that the expression of related proteins in VDR mTOR signal pathway changed. DDIT4 treatment could increase the expression of VDR, and reduce the expression of mTOR, p70s6k, 4E-BP1. The autophagy level showed that DDIT4 treatment could increase the expression of LC3I and decrease the expression of LC3II. The results of ferroptosis detection showed that DDIT4 treatment could reduce the expression of MDA and increase the expression of SOD and GSH. By participating in the VDR/mTOR/p70s6k/4E-BP1 signaling pathway, DDIT4 affects the process of autophagy and ferroptosis, thereby improving the pathological damage of diabetic kidney disease, and may become a new target for the treatment of DKD.