Abstract WP18: Hepatic Copper Dysregulation Induced Neuronal Cuproptosis in Ischemic Stroke: Insights Into Mechanisms and Therapeutic Efficacy of Remote Liver Hypothermia

Abstract

Objective: Serum copper level was increased in ischemic stroke, which was associated with disorder in hepatic copper metabolism. This study aims to determine the link between the elevation in serum copper levels following ischemic stroke, the consequent disorder in hepatic copper metabolism, and copper-induced neuronal death (cuproptosis). We sought to elucidate the role of remote administration of hypothermia (RAH) in liver, attenuating these detrimental processes and mitigating associated brain injuries. Methods: We subjected 80 adult Sprague-Dawley rats to 2-h middle cerebral artery occlusion (MCAO) followed by 6, 24 or 48 h reperfusion. Brain damage was evaluated by infarct volume, neurological deficit, and apoptotic cell death. Cuproptosis was measured by cerebral copper content and expressions of copper uptake protein (SLC31A1) and mitochondrial function proteins (SDHB, LIAS, FDX1, DPYD). Liver injury was determined by AST, ALT, and LDH in serum. Hepatic and serum copper metabolism, and regulatory molecules (HIF-1α, ceruloplasmin) were measured. In order to suppress liver copper metabolism and thus brain cuproptosis, RAH in liver was conducted 30 minutes pre-reperfusion. Results: Significant infarction, neurological deficit, and heightened apoptotic cell death were observed after stroke. Cerebral copper content and SLC31A1 expression were increased, while expressions of SDHB, LIAS, FDX1, and DPYD were diminished post-ischemic stroke, indicating a mitochondrial-related neuronal cuproptosis. 24 h post-reperfusion, there was a surge in serum liver injury markers. HIF-1α and ceruloplasmin were increased in liver post-stroke, with a concomitant decrease in hepatic copper and increase in serum copper levels. RAH mitigated hepatic copper imbalance and lowered serum copper via the HIF-1α/ceruloplasmin pathway, thus significantly attenuated neuronal cuproptosis, minimizing brain injury. Conclusions: The increase of cerebral copper content in ischemic stroke was derived by liver, which, in turn, intensified mitochondrial-related neuronal cuproptosis, exacerbating brain injury. RAH effectively counteracted the hepatic copper imbalances and hampered neuronal cuproptosis, producing neuroprotective benefits.