Otx2-PNN Interaction to Regulate Cortical Plasticity

Figure 1

Otx2-PNN feedback loop for critical period plasticity. At critical period (CP) onset, sensory activity induces initial formation of the perineuronal nets (PNNs), allowing the internalization of extracortical Otx2 by PV-cells. During CP, the increasing PV-cell Otx2 content enhances PNN assembly. In turn, PNNs ensure the specific accumulation of Otx2 in the PV-cells. In the adult, the constant transfer of Otx2 into the PV-cells, due to the positive feedback loop between the homeoprotein and the PNNs, maintains a mature, consolidated, nonplastic state. Indeed, interfering with Otx2-PNN interaction in the adult (by injecting ChABC to remove PNNs or by infusing the GAG-binding domain of Otx2 (RK-peptide) or a CS-E analogue to block Otx2) reopens a window of plasticity in the visual cortex.