Mitochondrial Damage Causes Inflammation via cGAS-STING Signaling in Acute Kidney Injury

Abstract

Summary: Acute kidney injury (AKI) is characterized by mitochondrial dysfunction and activation of the innate immune system. The cyclic GMP-AMP synthase (cGAS) stimulator of interferon genes (STING) pathway detects cytosolic DNA and induces innate immunity. Here, we investigate the role of mitochondrial damage and subsequent activation of the cGAS-STING pathway using a genetically engineered animal model of cisplatin-induced AKI and cultured tubular cells. Cisplatin induced mtDNA leakage into the cytosol—probably through BCL-2-like protein 4 (BAX) pores in the mitochondrial outer membrane—in tubules, with subsequent activation of the cGAS-STING pathway, thereby triggering inflammation and AKI progression, which is improved in STING-deficient mice. STING knockdown in cultured tubular cells ameliorates inflammatory responses induced by cisplatin. mtDNA depletion and repletion studies support tubular inflammatory responses via the cGAS-STING signal activation by cytosolic mtDNA. Therefore, we conclude that mitochondrial dysfunction and subsequent activation of the mtDNA-cGAS-STING pathway is a critical regulator of kidney injury. : Acute kidney injury (AKI) is associated with tubular inflammation and mitochondrial dysfunction. Maekawa et al. reveal that tubular mitochondrial damage leads to mtDNA leakage into the cytosol, probably via BAX pores on the mitochondria, activating cGAS-STING signaling and subsequent tubular inflammation in cisplatin-induced AKI. Suppression of the STING ameliorates tubular inflammation and progression of AKI. Keywords: acute kidney injury, tubular cells, mitochondrial DNA, inflammation, cGAS-STING pathway, cisplatin nephrotoxicity