PhD Student/Graduate Student Cedars-Sinai Board of Governors Regenerative Medicine Institute, United States
Abstract: Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease characterized by the degeneration of motor neurons (MNs), leading to paralysis and death. A defining feature of ALS is the selective vulnerability of MNs in different regions of the nervous system. Whether cervical, lumbar, or hindbrain MNs degenerate first determines the site of disease onset. Contemporary iPSC-derived models (iMNs) predominantly generate hindbrain and cervical MNs. Thus, they fail to capture the full spectrum of regional identities and potentially distinct pathogenic events, particularly those of lumbar MNs. Additionally, the heterogeneous nature of these models, which often produce mixed populations of MNs, can obscure critical region-specific characteristics and mechanisms of vulnerability, limiting their ability to fully model ALS pathology. To address these limitations, we optimized differentiation protocols by incorporating small molecules to direct the development of hindbrain/cervical and lumbar MN identities within 32 days. These protocols are reproducible across multiple healthy control and ALS cell lines, generating iMNs that closely resemble human spinal motor neurons with distinct segmental identities. Compared to traditional iMN induction methods, these optimized protocols produce iMNs with higher homogeneity and more well-defined hindbrain/cervical or lumbar identities. Notably, the protocols preserve limb-innervating markers, which are critical for accurately modeling the vulnerabilities observed in limb-onset ALS patients. This enhanced consistency and regional specificity provide a robust platform for studying region-specific motor neuron properties and offer new opportunities to explore the diverse roles of spinal motor neurons in health and disease with greater precision.
Funding Source: California Institute for Regenerative Medicine (CIRM): EDUC4-12751
