Modeling oxidative injury response in human kidney organoids

Abstract BackgroundPersistent acute kidney injury (AKI) leads to tubular atrophy, kidney fibrosis, and, if severe enough, chronic kidney disease (CKD). A common feature of AKI is the generation of excessive reactive oxygen species (ROS) which damage cells and induce inflammation. MethodsHuman kidney organoids were treated with hemin, an iron-containing porphyrin derived from lysed red blood cells, that generates ROS in disease settings such as rhabdomyolysis, sepsis and ischemia reperfusion leading to AKI. In addition, we developed an induced pluripotent stem cell line expressing the biosensor, CytochromeC-GFP (CytoC-GFP), which provides a real-time readout of mitochondrial morphology, health, and early apoptotic events. ResultsWe found that hemin-treated kidney organoids show oxidative damage, increased expression of injury markers, impaired functionality of organic anion and cation transport and undergo fibrosis. Tubule injury could be detected in live CytoC-GFP organoids by cytoplasmic localization of fluorescence. Finally, we show that 4-(phenylthio)butanoic acid, an HDAC inhibitor with anti-fibrotic effects in vivo , reduces hemin-induced human kidney organoid fibrosis. ConclusionTogether this work establishes a hemin-induced model of kidney organoid injury and fibrosis as a new model to study renal repair and a human platform for developing AKI therapeutics.