Metallothionein-2A Protects Cardiomyocytes from Hypoxia/reper-Fusion through Inhibiting p38

MT2A promotes angiogenesis in chronically ischemic brains through a copper-mitochondria regulatory mechanism

BACKGROUND

Approximately half of patients with chronic ischemic cerebrovascular disease (CICD) exhibit poor revascularization. Metallothionein 2 A (MT2A) has a high affinity for metal ions and is potentially capable of chelating toxic copper ions to alleviate the impairment of angiogenesis. Therefore, we hypothesized that MT2A could promote angiogenesis in chronically ischemic brains by neutralizing excessive copper ions during copper overload (CPO).

METHODS

We first collected dura matter (DM) samples from CICD patients and examined the expression of cuproptosis-related genes (DLAT, FDX1, and SDHB) to confirm the inhibitory effect of CPO on angiogenesis. Then, we treated human umbilical vein endothelial cells (HUVECs) with different concentrations of elesclomol and CuCl2 to determine the optimal concentration for inducing CPO. HUVEC activity and mitochondrial structure and function were detected to explore the ability of MT2A to alleviate CPO-induced damage. Finally, a rat model of 2-vessel occlusion plus encephalo-myo-synangiosis (2VO + EMS) with CPO was established to test the proangiogenic effect of MT2A through the 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. The optimal drug concentration for inducing CPO was subsequently determined, and in vitro experiments revealed that HUVEC activity was significantly decreased in the CPO group under hypoxic culture, accompanied by increased DLAT oligomerization, decreased SDHB expression, increased HSP70 expression. Moreover, significantly more common mitochondrial aberrations and significantly lower mitochondrial activity were detected in the CPO group compare with the control group. Additionally, MT2A overexpression alleviated CPO-induced mitochondrial dysfunction and cytotoxicity, improving HUVEC viability. In vivo, a CPO rat model was established, and CPO inhibited cerebral angiogenesis in 2VO + EMS model rats. Moreover, significantly greater CD31 expression, less DLAT accumulation, more mitochondria, and fewer mitochondrial abnormalities were observed in the CPOMT2A+ group than in the CPO group, accompanied by significantly improved cerebral blood perfusion and cognitive function.

CONCLUSION

MT2A can promote angiogenesis in chronically ischemic brains by neutralizing excessive copper ions and rescuing CPO-induced mitochondrial dysfunction.

Compensatory upregulation of MT2A alleviates neurogenic intermittent claudication through inhibiting activated p38 MAPK-mediated neuronal apoptosis

Neurogenic intermittent claudication (NIC), a classic symptom of lumbar spinal stenosis (LSS), is associated with neuronal apoptosis. To explore the novel therapeutic target of NIC treatment, we constructed the rat model of NIC by cauda equina compression (CEC) method and collected dorsal root ganglion (DRG) tissues, a region responsible for sensory and motor function, for mRNA sequencing. Bioinformatic analysis of mRNA sequencing indicated that upregulated metallothionein 2A (MT2A), an apoptosis-regulating gene belonging to the metallothionein family, might participate in NIC progression. Activated p38 MAPK mediated motor dysfunction following LSS and it was also found in DRG tissues of rats with NIC. Therefore, we supposed that MT2A might affect NIC progression by regulating p38 MAPK pathway. Then the rat model of NIC was used to explore the exact role of MT2A. Rats at day 7 post-CEC exhibited poorer motor function and had two-fold MT2A expression in DRG tissues compared with rats with sham operation. Co-localization analysis showed that MT2A was highly expressed in neurons, but not in microglia or astrocytes. Subsequently, neurons isolated from DRG tissues of rats were exposed to hypoxia condition (3% O2, 92% N2, 5% CO2) to induce cell damage. Gain of MT2A function in neurons was performed by lentivirus-mediated overexpression. MT2A overexpression inhibited apoptosis by inactivating p38 MAPK in hypoxia-exposed neurons. Our findings indicated that high MT2A expression was related to NIC progression, and MT2A overexpression protected against NIC through inhibiting activated p38 MAPK-mediated neuronal apoptosis in DRG tissues.