UCP2 and renal fibrosis: The main findings of this study are as follows: (1) circMTND5 localized to mitochondria and was the most downregulated circRNA in LN biopsies, (2) circMTND5 served as a sponge of MIR6812 in human kidney tissues and HK-2 renal tubular cells, and (3) circMTND5/MIR6812/UCP2 pathway participated in renal mitochondrial injury and renal fibrosis in LN (Figure 9).