2014 Articles

Synchronized renal tubular cell death involves ferroptosis

Linkermann, Andreas; Mulay, Shrikant; Skouta, Rachid; Himmerkus, Nina; Dewitz, Christin; De Zen, Federica; Zuchtrieger, Gabriele; Prokai, Agnes; Krombach, Fritz; Welz, Patrick-Simon; Weinlich, Ricardo; Berghe, Tom Vanden; Vandenabeele, Peter; Reichel, Christoph A.; Kunzendorf, Ulrich; Bleich, Markus; Pasparakis, Manolis; Stockwell, Brent R.; Anders, Hans-Joachim; Weinberg, Joel; Brasen, Jan Hinrich; Green, Douglas; Krautwald, Stefan

Receptor-interacting protein kinase 3 (RIPK3)-mediated necroptosis is thought to be the pathophysiologically predominant pathway that leads to regulated necrosis of parenchymal cells in ischemia–reperfusion injury (IRI), and loss of either Fas-associated protein with death domain (FADD) or caspase-8 is known to sensitize tissues to undergo spontaneous necroptosis. Here, we demonstrate that renal tubules do not undergo sensitization to necroptosis upon genetic ablation of either FADD or caspase-8 and that the RIPK1 inhibitor necrostatin-1 (Nec-1) does not protect freshly isolated tubules from hypoxic injury. In contrast, iron-dependent ferroptosis directly causes synchronized necrosis of renal tubules, as demonstrated by intravital microscopy in models of IRI and oxalate crystal-induced acute kidney injury. To suppress ferroptosis in vivo, we generated a novel third-generation ferrostatin (termed 16-86), which we demonstrate to be more stable, to metabolism and plasma, and more potent, compared with the first-in-class compound ferrostatin-1 (Fer-1). Even in conditions with extraordinarily severe IRI, 16-86 exerts strong protection to an extent which has not previously allowed survival in any murine setting. In addition, 16-86 further potentiates the strong protective effect on IRI mediated by combination therapy with necrostatins and compounds that inhibit mitochondrial permeability transition. Renal tubules thus represent a tissue that is not sensitized to necroptosis by loss of FADD or caspase-8. Finally, ferroptosis mediates postischemic and toxic renal necrosis, which may be therapeutically targeted by ferrostatins and by combination therapy.