Genipin rescues developmental and degenerative defects in familial dysautonomia models and accelerates axon regeneration

The peripheral nervous system (PNS) is essential for proper body function. A high percentage of the world’s population suffers nerve degeneration or peripheral nerve damage. Despite this, there are major gaps in the knowledge of human PNS development and degeneration and therefore, there are no available treatments. Familial Dysautonomia (FD) is a devastating disorder caused by a homozygous point mutation in the gene ELP1. FD specifically affects the development and causes degeneration of the PNS. We previously employed patient-derived induced pluripotent stem cells (iPSCs) to show that peripheral sensory neurons (SNs) recapitulate the developmental and neurodegenerative defects observed in FD. Here, we conducted a chemical screen to identify compounds that rescue the SN differentiation inefficiency in FD. We identified that genipin restores neural crest and SN development in patient derived iPSCs and in two mouse models of FD. Additionally, genipin prevented FD degeneration in SNs derived from patients with FD, suggesting that it could be used to ameliorate neurodegeneration. Moreover, genipin crosslinked the extracellular matrix (ECM), increased the stiffness of the ECM, reorganized the actin cytoskeleton, and promoted transcription of YAP-dependent genes. Finally, genipin enhanced axon regeneration in healthy sensory and sympathetic neurons (part of the PNS), and in prefrontal cortical neurons (part of the central nervous system), in in vitro axotomy models. Our results suggest that genipin has the potential to treat FD-related neurodevelopmental and neurodegenerative phenotypes, and to enhance neuronal regeneration of healthy neurons after injury. Moreover, this suggests that the ECM can be targeted to treat FD. To study the effects of genipin in FD, we differentiated iPSC-FD-S3 cells into SNs with or without genipin. Genipin (10 μM) was added to the media of the treated cells throughtout the differentation. To characterize their transcriptome, we collected RNA on day 20. We also collected RNA from untreated healthy SNs (day 20) differentiated from hPSC-ctr-H9 cells. We performed RNAseq of each sample.