PIK3R1 and brain ischemia: First, the results of in vivo experiments (Table 3) showed that GRb1 protected hippocampal CA1 neurons (Lim et al., 1997), reduced free radicals (Chen et al., 2015), and possessed potential for treating brain injuries (Yang et al., 2008); meanwhile, GRb1 increased superoxide dismutase (SOD) activity, decreased malondialdehyde (MDA) contents in the serum and spinal cord tissue (Ye et al., 2019), and inhibited oxidative stress and extracellular signal-regulated kinase (ERK) activation in aged mice exposed to cerebral ischemia (Dong et al., 2017).