Runx1-Snx9 axis drives the pathological secretion of mitochondrial-derived vesicles to activate cGAS-STING signaling in acute pancreatitis.

In acute pancreatitis (AP), the release of mitochondrial DNA (mtDNA) from pancreatic acinar cells (PACs) plays a pivotal role in triggering a lethal systemic inflammatory response. Despite the importance of mtDNA release, the regulatory mechanisms upstream of this event remain poorly understood, hindering the development of targeted therapeutic strategies. To address this, we utilized single-cell RNA sequencing, CUT&Tag, luciferase reporter assays, and experiments in a PAC-specific knockout mouse model to investigate the transcriptional program governing vesicle transport and mtDNA release in the context of AP. Our analysis revealed that vesicle transport pathways were activated in AP PACs and identified Runx1 as a core transcriptional regulator. We discovered that Runx1 directly binds and activates the Snx9 promoter. This interaction initiates a pathological cascade wherein Runx1-Snx9 signaling drives mitochondrial fragmentation and the biogenesis of intracellular mitochondrial-derived vesicles (MDVs). Under AP conditions, these MDVs are diverted from degradative pathways and routed to the secretory machinery to be released as pathogenic, extracellular mitochondrial-derived vesicles (Ex-MDVs). These Ex-MDVs were confirmed to be highly pathogenic, strongly activating the cGAS-STING pathway in macrophages. Notably, PAC-specific deletion of Runx1 in a mouse model significantly mitigated pancreatic injury and suppressed the systemic inflammatory storm associated with AP. This study is the first to elucidate the Runx1-Snx9 transcriptional axis as the core upstream mechanism responsible for the anomalous generation and secretion of Ex-MDVs from PACs during AP, providing novel insights into AP pathogenesis and identifying this axis as a potential therapeutic target.