Endolysosomal protease leakage reprograms macrophage mitochondrial metabolism

Organelle crosstalk plays important functions in metabolic processes and is relevant to immunity, neurodegeneration, and cancer. The permeabilisation and rupture of endolysosomes during stress can induce inflammation and cell death. There is growing evidence that endomembrane damage does not always result in cell death and that important cellular functions can be regulated by limited endolysosomal damage. However, the effect of limited cytosolic leakage of endolysosomal contents on the function of other cytoplasmic organelles is poorly understood. Here, we show that sterile and non-sterile endolysosomal damage triggers remodelling of the mitochondrial proteome and metabolic reprogramming of human macrophages. Mitochondrial metabolic reprogramming was associated with endolysosomal leakage independently of proteasome degradation and mitophagy. Furthermore, single-cell RNA-sequencing and metabolic analysis of lung macrophages undergoing endomembrane damage showed altered mitochondrial metabolism in mice. We, therefore, uncover an inter-organelle communication mechanism between mitochondria and endolysosomes with limited proteolytic leakage, providing a general mechanism by which macrophages undergo mitochondrial metabolic reprogramming in response to infection or injury.