Loss of Thioredoxin-1 in central nervous system neurons results in cerebellar ataxic behavioral deficits

Reversible oxidation of protein thiols is an important signaling paradigm to modulate protein activity during redox perturbations. Protein thiol oxidation and reduction are regulated by the thioredoxin and glutathione enzyme superfamilies. Thioredoxin 1 (Trx1) is ubiquitous to all life and its oxidoreductase activity is associated with resistance from a myriad of oxidative insults. Although the physiological relevance of thiol switch regulation is largely unknown, Trx1 activity has been implicated in the pathogenesis of numerous diseases including neurodegeneration and peripheral neuropathy. Utilizing Cre-lox transgenic systems, we are able to drive a neuron specific loss of Trx1 in brain, spinal cord, and dorsal root ganglion (DRGs), allowing us to investigate the effects of a loss of Trx1 in the central nervous system (CNS). Since neurons are highly susceptible to redox perturbations and oxidative stress, we will determine how knockdown of Trx1 activity in neurons influences neurodevelopment, neuropathology, and behavior. Trx1fl/fl; Syn1-Cre+ mice exhibit seizures and ataxic behavioral deficits compared to Trx1fl/+; Syn1-Cre+ and Syn1-Cre+ controls, suggesting perturbations in neural development and/or maintenance. Ledge, gait, hind limb and force plate testing at 4, 6 and 8 weeks shows increasing seizures and ataxic decline after a loss of Trx1, with Trx1fl/fl; Syn1-Cre+ mice ultimately only surviving to approximately 10 weeks of age. In addition to behavioral analysis, we will perform immunohistochemistry (IHC) to investigate changes in interneuron makers, inhibitory signaling molecules, and expression of the neuronal structural protein CRMP2 – a known interactor of Trx1. Complimentary to IHC, Nissl staining will reveal any changes in brain morphology and cell numbers. Fundamental knowledge gained from this project will advance our understanding of Trx1-dependent signaling in neurons and provide new understanding for how reversible oxidation of protein thiols regulates physiological responses to redox perturbations during neurodevelopment and oxidative neurological disorders.