Cryptotanshinone Targets HYOU1 to Rewire ER-Mitochondria Communication and Enhance Autophagy in Atherosclerosis

Atherosclerosis is driven by chronic lipid accumulation, oxidative stress, and impaired autophagy, yet effective therapies targeting these pathways remain elusive. Oxidized low-density lipoprotein (oxLDL), a major contributor to atherosclerosis, disrupts cellular homeostasis by promoting the formation of mitochondria-associated ER membrane (MAM), which regulate essential processes such as calcium transport, lipid metabolism, mitochondrial dynamics, and autophagy—critical components in atherosclerotic signaling pathways. Here, we identify hypoxia-upregulated protein 1 (HYOU1) as a novel regulator of MAM stability, coordinating ER-mitochondrial calcium flux and lipid metabolism. Using DARTS-LC-MS/MS, we demonstrate that cryptotanshinone (CTS), a natural anti-atherosclerotic compound derived from Danshen ( Salvia miltiorrhiza ), binds directly to the nucleotide-binding domain (NBD) of HYOU1, disrupting ER-mitochondria interactions. This results in three key outcomes: (1) increased cytosolic calcium levels and TFEB nuclear translocation, (2) decreased mitochondrial calcium influx and ATP production, and (3) enhanced autophagy, which reduces intracellular lipid accumulation. Consequently, CTS reduces mitochondrial ROS accumulation and lipid overload in vitro , while alleviating atherosclerotic burden in ApoE-/- mice fed a high-cholesterol diet. Single-cell transcriptome analysis of human carotid atherosclerotic plaques further revealed that HYOU1 and its associated autophagy and lipid metabolism regulators are upregulated in monocytes and dendritic cells, underscoring their clinical relevance and co-regulated expression in atherosclerotic lesions. These findings provide the first evidence that HYOU1 as a promising therapeutic target for modulating MAM-autophagy crosstalk and highlight CTS as a potential small-molecule intervention to disrupt the oxLDL-driven atherosclerotic cycle.