Marcks overexpression in retinal ganglion cells promotes optic nerve regeneration

Regeneration of injured central nervous system (CNS) axons is highly restricted, leading to permanent neurological deficits. The myristoylated alanine-rich C-kinase substrate (MARCKS) is a membrane-associated protein kinase C (PKC) substrate ubiquitously expressed in eukaryotic cells, plays critical roles in development, brain plasticity, and tissues regeneration. However, little is known about the role of Marcks in CNS axon regeneration. Here we show that Marcks overexpression promotes robust axon regeneration either before or after optic nerve crush, but insignificantly impacts neuronal survival. Notably, immunostaining and RNA sequencing demonstrate that Marcks overexpression does not affect known regeneration-associated genes and pathways. Furthermore, combining CNTF which activates the JAK-STAT3 pathway and Marcks overexpression further enhances axon regeneration. Finally, we demonstrate functionally essential effector domain (ED) of MARCKS has similar effects on inducing axon regeneration in RGCs. These results suggest that manipulating Marcks and its ED may become a therapeutic approach to promote axon regeneration after CNS injury.