Design and evaluation of EphrinA1 mutants with cerebral protective effect

Abstract

The activation of EphA2 receptor by its natural ligand EphrinA1 causes blood brain barrier dysfunction, and inactivation of EphA2 reduces BBB damage in ischemic stroke. Thus, EphA2 targeted antagonists may serve as neuroprotective agents. We engineered four mutants of EphrinA1, EM1, EM2, EM3 and EM4, respectively. The computational analysis showed that these four mutants were capable of interacting with EphA2. Their potential neuroprotective effects were examined in mouse focal ischemia/reperfusion (I/R) model. EM2 exhibited strong neuroprotective effects, including reduced brain infarct volume, neuronal apoptosis, cerebral edema, and improved neurological scores. The EM2-mediated protection was associated with a comparative decrease in BBB leakage, inflammatory infiltration, and higher expression levels of tight junction proteins, such as zonula occludens-1 and Occludin. I/R-induced high expression of Rho-associated protein kinase 2 (ROCK2) was down-regulated after EM2 treatment. Moreover, EM2 reduced agonist doxazosin-induced EphA2 phosphorylation and cells rounding in PC3 cells, indicating EphA2-antagonizing activity of EM2. These finding provided evidences of the neuroprotection of EphA2 antagonist and a novel approach for ischemic stroke treatment. These results also suggested that a receptor agonist can be switched to an antagonist by substituting one or more relevant residues.

Participation of Amyloid and Tau Protein in Post-Ischemic Neurodegeneration of the Hippocampus of a Nature Identical to Alzheimer's Disease

“…So far, there is no specific treatment option that can prevent the subsequent neurofunctional dysfunction due to the damage of the hippocampal CA1 region in particular. Until recently, based on the above-mentioned mechanisms, many researchers are still trying to develop effective neuroprotective agents against experimental cerebral ischemia, with more attention paid to changes in the hippocampus [ 21 , 22 ]. The latest findings show that most neuroprotective agents that have been proved to be effective in experimental models of cerebral ischemia do not provide a significant benefit in clinical trials [ 23 ].…”

Increased Serum EphrinA1 Is Associated with Parenchymal Hematoma after Ischemic Stroke

“…Blood-brain barrier (BBB) disruption is suggested to be an important underlying mechanism of PH after ischemic stroke [3]. Eph-Ephrin, the largest tyrosine kinase family, is involved in multiple pathophysiological processes including ischemia-reperfusion, central nervous system peripheral immune cell infiltrates, and BBB disruption [4]. Several EphA receptors and EphrinA ligands were found to be expressed in microvascular endothelial cells of human brains [5], and higher EphrinA1 levels were associated with higher permeability of microvascular endothelial cells [6].…”