Friday, January 3, 2025
1/3/2025
PROJECT SUMMARY/ABSTRACT In motor neuron diseases, neuromuscular junctions are lost and motor neurons degenerate resulting in progressive paralysis and death. Post-transcriptional gene regulation by microRNAs (miRNAs) is hypothesized to be disrupted in motor neuron diseases due to inherited mutations in proteins involved in miRNA processing, such as TDP43, FUS, and SMN. Yet, the role of specific miRNAs in human motor neuron gene regulation and function is not well characterized. I previously discovered that a single miRNA, miR-218, is uniquely enriched and abundantly expressed in mouse motor neurons. Furthermore, mice lacking miR-218 exhibited deficits in neuromuscular synaptogenesis and die due to muscle paralysis – phenotypes associated with motor neuron disease. Subsequent studies have implicated miR-218 dysregulation as a mediator of motor neuron disease in humans. However, the relationship between miR-218’s repression of target gene pathways and motor neuron phenotypes has not been resolved, and the biological role of miR-218 has not been previously investigated in humans, leaving an important translational gap in our knowledge of human motor neuron gene regulation and function. In response to this challenge, we in the Pasca Lab have recently developed a three-dimensional, human induced pluripotent stem (hiPS) cell-derived model of human motor neuron development and function, called cortico-motor assembloids, by fusing cortical, spinal, and skeletal muscle spheroids. Dr. Amin proposes using this novel system to model the impact of miR-218 upon motor neuron development, target pathways, and human specific-features of post-transcriptional gene regulation. This proposal will leverage Dr. Amin’s existing proficiencies in motor neuron development, miRNA biology, and advanced transcriptomics and will enable new career development training in stem cell biology and human brain organoid models with mentor Dr. Sergiu Pasca. Dr. Amin will utilize the exceptional research environment and resources available at Stanford University. He will be supported by his advisory committee comprising of Dr. Howard Chang, an expert in non-coding RNA mediated gene regulation, Dr. Aaron Gitler, an expert in motor neuron biology and disease pathways, and Dr. Richard Reimer, a practicing neurologist and expert in disease pathogenesis. Completion of this proposal will pave the way for further investigations into the therapeutic modulation of miR-218 and its target mRNAs in human motor neuron disease.
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