HDAC4 and COVID-19: Since NRP1 [41], HDAC4 [21], CREB [42] and RIPK1 [43] protein dysregulation has been found to contribute independently to neuronal death in in vitro and in vivo stroke models [21] and that patients with COVID‐19 should undergo more aggressive stroke outcome [31, 44, 45], we examined whether S1rp and the experimental conditions mimicking brain ischemia OGD/Rx could have an additive effect in increasing neuronal death by modulating the NRP1/HDAC4/CREB/RIPK1 axis.