Modifying PTEN recruitment promotes neuron survival, regeneration, and functional recovery after CNS injury

Phosphatase and tensin homolog (PTEN) regulates apoptosis and axonal growth in the developing and adult central nervous system (CNS). Here, we show that human PTEN C-terminal PDZ interactions play a critical role in neuronal apoptosis and axon regeneration after traumatic CNS injury and stroke, highlighted by the findings that antagonizing the PDZ-motif interactions of PTEN has therapeutic applicability for these indications. Interestingly, the death-inducing function of PTEN following ischemic insult depends on a PDZ-domain interaction with MAGI-2 and MAST205, PDZ proteins that are known to recruit PTEN to the plasma membrane and stabilize its interaction with PIP3. Treatments with a human peptide that prevents PTEN association with MAGI-2 or MAST205 increased neuronal survival in multiple stroke models, in vitro. A pro-survival effect was also observed in models of retinal ischemia, optic nerve transection, and after middle cerebral artery occlusion (MCAO) in adult rats. The human PTEN peptide also improved axonal regeneration in the crushed optic nerve. Furthermore, human PTEN peptide therapy promoted functional improvement after MCAO or retinal ischemia induced via ophthalmic artery ligation. These findings show that the human peptide-based targeting of C-terminal PTEN PDZ interactions has therapeutic potential for insults of the CNS, including trauma and stroke.