Exploring mitophagy levels in Drosophila Malpighian tubules unveils the pivotal role of mitophagy in kidney function and diabetic kidney disease

Mitophagy has been implicated in kidney function and related diseases. However, a direct analysis of mitophagy in kidney models, including disease models, remains notably lacking. Here we analyzed mitophagy levels in Drosophila Malpighian tubules, a functional analog of the human kidney, using a transgenic model of the engineered mitophagy reporter mt-Keima. We found that mitophagy is highly active in the major cell types of the Malpighian tubules, including renal stem cells, principal cells and stellate cells. Notably, the suppression of mitophagy by genetic downregulation of mitophagy-related genes, such as ATG5 and ULK1, led to a significant decrease in the secretion function of the Malpighian tubules, suggesting that mitophagy is essential for their proper function. Interestingly, a continuous high-sugar diet, which is used as a model for diabetic kidney disease, caused a reduction in mitophagy levels in principal cells before the development of mitochondrial dysfunction and defective secretion. Importantly, stimulation of mitophagy with the recently developed mitophagy inducer PDE701 rescued both mitochondrial dysfunction and defective phenotypes in a diabetic kidney disease model. Our results highlight the pivotal role of mitophagy in kidney function and suggest that modulating mitophagy could be a potential strategy for treating kidney diseases.