Date of Award
Doctor of Philosophy (PhD)
Spinal cord injury (SCI) leads to loss of motor function among other devastating impairments, with patients having a grim outlook on recovery as currently there are no widely efficacious treatment methods. The native regenerative capacity of the neurons in the central nervous system is limited, thus recovery of the axonal connections between the different components of the complex circuitry that enables motor function is minimal after SCI. Investigators aiming to improve motor function post-SCI approach the problem from different angles, including removing inhibitory elements to axonal regeneration and supporting regeneration through implantation of biomaterials, exposure to pro-regenerative factors, and transplantation of cells. For cell transplantation, populations to consider include the spinal interneurons (INs), with the ventral IN (vIN) subtypes known to have roles in motor circuits and having previously been shown to contribute to functional recovery in rodent SCI models. Among the vINs, those that release excitatory neurotransmitters are especially of interest for regenerative therapies, as they can lead to motor neuron stimulation and thus functional output. One vIN subtype is the V0 INs, which are diverse, largely with commissurally projecting-axons, and broadly include a dorsal, inhibitory population - V0D INs - and a ventral, excitatory population - V0V INs. To obtain a sufficient number of INs for further study and transplantation, deriving them by differentiating pluripotent stem cells (PSCs) is practical method. However, induction protocols yield heterogenous cultures, and thus a means of selecting the desired population is necessary. One selection method involves creating a transgenic PSC line by inserting an antibiotic resistance gene into a cell-specific gene locus. This dissertation will include work on deriving the V0V IN population from a PSC source, mouse embryonic stem cells, and generating a transgenic mouse embryonic stem cell line to enable selection of V0V INs from induced cultures, thus providing tools for future investigations using V0V INs as a therapeutic, transplantable population.
Dennis Barbour Shelly Sakiyama-Elbert
Martha Bagnall, Aaron DiAntonio, James Huettner, Jonathan Silva,