Engineered Tan-CDs@AS-IV Nanosystem Orchestrates Mitochondrial Biogenesis and Intercellular Transfer to Restore Endothelial Function via PGC-1α and Cx43 Signaling Pathways

Ischemic diseases are characterized by the functional collapse of endothelial cells (ECs) triggered by insufficient tissue perfusion. Given that mitochondria serve as the metabolic hub of ECs, their homeostatic imbalance, which is manifested by adenosine triphosphate (ATP) depletion, Reactive Oxygen Species (ROS) bursts, and mitochondrial permeability transition pore opening, serves as the initiating factor driving impaired angiogenesis and tissue necrosis. In this study, we engineered an integrated nanosystem (Tan-CDs@AS-IV) by transforming Tanshinone into antioxidant carbon dots to encapsulate Astragaloside IV, achieving multi-level synergistic regulation of mitochondrial function. Our results demonstrate that Tan-CDs@AS-IV possesses superior structural stability and cellular internalization capabilities, significantly enhancing the migration and tubulogenesis of ECs under ischemic stress. Mechanistically, Tan-CDs@AS-IV effectively scavenges mitochondrial ROS and restores membrane potential and ATP production. Crucially, the nanosystem orchestrates mitochondrial biogenesis via Peroxisome Proliferator-activated Receptor γ coactivator 1-α (PGC-1α) upregulation while simultaneously facilitating intercellular mitochondrial transfer through Connexin 43 (Cx43)-mediated gap junctions. This synergistic "endogenous amplification and intercellular replenishment" model establishes a robust mitochondrial quality control relay. By reconstructing cellular energy homeostasis, this study provides a novel nanoengineering strategy for the targeted therapy of ischemic diseases.