It is currently unknown why mature, central nervous system (CNS) neurons fail to regenerate after injury, and how this failure depends on developmental changes in gene expression. Mature RGCs fail to regenerate after their axons are severed, yet axons in the embryonic CNS can regenerate after injury. The loss of this embryonic regenerative ability correlates with the loss of RGCs'intrinsic ability to rapidly extend axons. Here we propose to investigate the regulation of RGC axon growth and regenerative capacity by the Kruppel-Like family of transcription factors. Specifically, we have identified a family of developmentally regulated transcription factors in the Kruppel-Like Factor (KLF) family that regulate axon growth of RGCs in vitro and in vivo. In the first aim we determine how KLF family members differ in their recruitment of co-activators and co-repressors, and how such co- factors regulate RGC axon growth with the KLFs. In the second aim we will characterize the gene targets of KLF family members in RGCs in vitro and in vivo. In the third aim we will ask whether manipulating expression of multiple KLFs in vitro and in vivo alters RGC axon growth during development or after optic nerve injury. Our goal is to revert mature, postnatal RGCs to their embryonic axon growth ability, and to enhance RGC regeneration after optic nerve injury in vivo. Our ultimate goal is to develop new treatments to promote RGC regeneration after injury in ocular diseases including glaucoma, retinal ischemia, optic neuritis and optic neuropathies, and to extend our understanding to more broadly promote CNS regeneration, for example after spinal cord injury or in neurodegenerative disease.
Retinal ganglion cells (RGCs) lose their ability to regenerate, but it is not known why. Developmentally regulated transcription factors in the Kruppel-Like Factor family may control RGCs'intrinsic capacity for rapid axon growth and regeneration, but the cellular and molecular details of this process remain to be discovered. Our hope in investigating this process is to understand why RGCs fail to regenerate after injury or in degenerative diseases such as glaucoma and ischemic optic neuropathy.
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