MT2A Promotes Angiogenesis in Chronically Ischemic Brains through a Copper–Mitochondria Regulatory Mechanism

Background Recent studies have indicated that copper overload (CPO) has cytotoxic effects, and metallothionein 2A (MT2A) has a high affinity for metal ions. However, it is unclear whether MT2A can normalize endothelial cell (EC) proliferation and angiogenesis in chronically ischemic brains by neutralizing excessive copper ions during CPO. Methods Dura matter (DM) samples from patients with chronic ischemic cerebrovascular disease were collected, and the expression of cuproptosis-related genes (DLAT, FDX1 and SDHB) was determined. CPO in human umbilical vein endothelial cells (HUVECs) was induced by elesclomol and CuCl ₂ . HUVEC activity under hypoxia and the structure and function of mitochondria were compared among groups with different copper ion concentrations and different MT2A expression levels. Furthermore, a rat model of 2-vessel occlusion plus encephalo-myo-synangiosis (2VO + EMS) with CPO was established to explore the ability of MT2A to promote angiogenesis through a copper–mitochondria regulatory mechanism in chronically ischemic brains. Results Compared with those from Matsushima grade A patients, DM samples from Matsushima grade C patients presented significantly greater DLAT and FDX1 expression and significantly lower SDHB expression. HUVEC activity under hypoxia was significantly decreased in the CPO group. DLAT oligomerization was increased and SDHB expression was significantly decreased in the CPO group. Mitochondrial aberrations were significantly more common and mitochondrial activity was significantly lower in the CPO group than in the control group. MT2A overexpression alleviated the impairment of HUVEC activity and mitochondrial dysfunction induced by CPO. In vivo, CPO inhibited cerebral angiogenesis in 2VO + EMS model rats. CD31 expression was significantly greater in the CPO ^MT2A+ group than in the CPO group. DLAT accumulation was significantly less common in the CPO ^MT2A+ group than in the CPO group. Less mitochondrial swelling and fewer vacuoles were observed in the CPO ^MT2A+ group than in the CPO group. Cerebral blood perfusion (CBP) and performance in the Morris water maze test were better in the CPO ^MT2A+ group than in the CPO group. Conclusion CPO inhibits EC proliferation and angiogenesis by impairing mitochondrial structure and function, whereas MT2A promotes EC proliferation and angiogenesis by neutralizing excessive copper ions and rescuing mitochondrial function.