Una Questione di Distanza: la Localizzazione Perinucleare Mitocondriale Modella la Segnalazione dei ROS all’Interno del Nucleo

Mitochondria play a central role in regulating cellular functions, in a coordinated manner with the nucleus. Emerging evidence suggest the existence of specialized mito-nuclear contact sites (MNCs) that may serve as hubs for inter-organelle communication, potentially modulating reactive oxygen species (ROS)-dependent signaling pathways and their impact on nuclear functions. However, whether mitochondrial spatial organization directly regulates ROS-dependent nuclear signaling remains unclear. To shed light on this topic, we investigated how mitochondrial subcellular localization affects ROS production, diffusion, and downstream nuclear responses. We used an engineered cellular model to obtain controlled intracellular ROS generation, together with manipulation of mitochondrial subcellular localization, to directly compare normal and perinuclear mitochondrial distributions effects at the nuclear level. Quantitative live-cell imaging of nuclear ROS dynamics enabled us to monitor ROS nuclear levels under different mitochondrial localization conditions, allowing a deeper understanding of ROS nuclear scavenging capacity and spatial diffusion. Ultimately, DNA damage assessment upon different oxidative stress conditions, enabled the evaluation of functional consequences resulting from spatially restricted ROS signaling at the nuclear level. Our results show that mitochondrial positioning critically influences nuclear ROS exposure and downstream genomic integrity, supporting a model in which perinuclear mitochondrial clustering enhances localized oxidative stress, and influences DNA damage responses. Collectively, this work establishes a spatially resolved framework for dissecting mito-nuclear communication, highlighting mitochondrial localization as a key regulator of intracellular signaling, and furthering our understanding on the spatial basis of nuclear mtROS responses and adaptations.