CONVERSION OF REACTIVE GLIA INTO FUNCTIONAL NEURONS AS A NOVEL THERAPY FOR STROKE

Restricted (Penn State Only)
Author:
Chen, Yuchen
Graduate Program:
Molecular, Cellular and Integrative Biosciences
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
December 01, 2017
Committee Members:
  • Gong Chen, Dissertation Advisor
  • Yingwei Mao, Committee Chair
  • Timothy J Jegla, Committee Member
  • Bernhard Luscher, Committee Member
  • Ian Alexander Simpson, Outside Member
Keywords:
  • NeuroD1
  • ischemic injury
  • brain repair
  • astrocyte-to-neuron conversion
  • motor function
Abstract:
Stroke is a severe neurological disorder and a leading cause of disability and death, which affects millions of people worldwide. Recovery of stroke-injured brain is very limited, largely due to incapability of adult brain to regenerate enough new neuronal cells. We have recently developed an innovative in situ cell conversion technology to directly convert endogenous glial cells into functional neurons, but whether it could help functional recovery is not well studied. In this dissertation, we demonstrate that NeuroD1-mediated glia-to-neuron conversion can functionally rescue the motor deficits induced by the cerebral stroke in mice. Specifically, using a combination of hGFAP::Cre and FLEX-NeuroD1 AAV system, we were able to regenerate ~40% of cortical neurons (400 NeuN+ new neurons/mm2), compared to previously reported an average of <1% of cortical neurons (2-8 NeuN+ neurons/mm2) in an ischemic-injured adult mammalian cortex. Importantly, following injection of viral vectors carrying NeuroD1 into the stroke areas, not only were reactive glial cells converted into functional new neurons, but also the injured pre-existing neurons were better protected, leading to a repair of cortical tissue and neural circuits. In the NeuroD1-treated stroke areas, both neuroinhibitory and inflammatory factors significantly reduced, while blood vessels significantly increased, accompanied with a restoration of the blood-brain-barrier (BBB). These beneficial effects at cellular and circuits level led to a rescue of motor behavior deficits. Our studies suggest that in situ cell conversion from reactive glial cells into functional neurons may have the potential to treat stroke and related neurological disorders.