COX4I1 and brain ischemia: By targeting COX4I1, a COX IV isoform that is enriched in the brain, upregulating miR-338 in cerebral ischemia hinders COX IV protein synthesis and mitochondrial complex IV activity resulting in mitochondrial dysfunction and decreasing the ability of astrocytes to handle oxidative stress, and ultimately exacerbating ischemic brain injury (Li L. et al., 2021).