We are studying the molecular mechanisms that underpin disease onset and progression in inheritable neuropathies such as Amyotrophic Lateral Sclerosis (ALS) and Charcot-Marie-Tooth (CMT) disease employing in vitro cell cultures to produce disease-in-a-dish models. Cells derived from human patients are reprogrammed to produce induced pluripotent stem cells. In some cases these stem cells bear disease-causing gene mutations that were present in the patient. In other cases we employ CRISPR/cas9 gene editing to introduce disease-causing mutations. We differentiate these stem cells to produce motor neurons and sensory neurons. In addition to conventional monolayer cell culture techniques we are working to develop new organ-on-chip devices to provide better disease models.
Electrical activity recorded from human stem cell-derived motor neurons. Note that the ALS cells exhibit a reduced capacity to fire repetitive trains of electrical spikes.
Human stem cell derived neurons stained to highlight expression of neuronal markers, microtubule associated protein 2 (MAP-2) and neurofilament
CMT is the most common inherited neurological disorder. We are focusing on mechanisms responsible for CMT type 2, which specifically affects motor and sensory axons. Mutations of 5 different amino-acyl tRNA synthetases cause CMT2. Curiously, although the only shared function of these amino-acyl tRNA synthetases is support of mRNA translation, the prevailing view is that the mutated proteins have little effect on translation but cause disease by neomorphic toxic effects unrelated to protein synthesis. We are exploring a specific hypothesis that challenges this point of view employing in vivo, in vitro, and in silico approaches.
- Investigators: Alec Smith, Mark Bothwell, Matt Childers