Role of mitochondrial calcium uniporter in regulating mitochondrial fission in the cerebral cortexes of living rats.

The mitochondrial calcium uniporter (MCU) transports Ca from the cytoplasm to the mitochondrial matrix and thus maintains Ca homeostasis. Previous studies have reported that inhibition of MCU by ruthenium red (RR) protects the brain from ischemia/reperfusion (I/R) injury and that mitochondrial fission plays an important role in I/R injury. However, it is still not known whether MCU affects mitochondrial fission. In the present study, treatment with RR was found to decrease the concentration of free calcium in the mitochondria, calcineurin enzyme activity and dynamin-related protein 1 expression, and treatment with spermine was found to have the opposite effect in organisms subjected to occlusion of the middle cerebral artery lasting 2 h followed by 24 h reperfusion. These results indicate that MCU may be related to mitochondrial fission via modulating mitochondrial Ca uptake and this relationship between MCU and mitochondrial fission may protect the brain from I/R injury. [ABSTRACT FROM AUTHOR]