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Abstract
The autonomic nervous system (ANS) regulates involuntary responses of the body, such as heart rate, blood pressure, and respiration. Dysfunction of the ANS causes dysautonomia and will lead to symptoms that affect the whole body, including difficulty breathing and blood pressure dysregulation, which are usually unpredictable. Dysautonomia is involved in various neurodegenerative, genetic, and metabolic diseases, the pathological understanding of which is limited due to the lack of a human-based model system to study specific parts of the ANS. Here, to study ANS specific defects, I established human pluripotent stem cell (hPSCs)-derived ANS component cell types to model both genetic and sporadic dysautonomia. First, I used hPSC-sympathetic neurons (symNs) to model the genetic ANS disorder familial dysautonomia (FD), a neurodevelopmental and neurodegenerative disorder that mainly affects the ANS. Our hPSC-symNs modeled early developmental defects in FD, including impaired neural crest differentiation and low survival of symN precursors. We further discovered FD symN hyperactivity, which was caused by impaired norepinephrine transporter functionality. In addition to genetic disease, we also mimicked diabetic hyperglycemia as a sporadic dysautonomia model. We detected symN hyperactivity, which is known as an early indication of diabetic autonomic neuropathy. We further identified that the glucose sensor O-GlcNAcylation was involved in diabetic symN hyperactivity. Our symNs have even been used to study COVID19-induced dysautonomia. Moreover, cardiovascular neuropathy is one of the most common types of dysautonamia, thus we established a 3D cardiac organoid model that contains symN innervation to better recapitulate the complexity of heart neural networks. On the other hand, we differentiated hPSC-parasympathetic neurons (parasymNs) and found that FD parasymNs were also hyperactive and showed disconnected communication with the sympathetic system. Finally, we established a protocol to differentiate the adrenal chromaffin cells, which is a critical stress responding center in addition to the SNS, are considered as specialized symNs. Together, my work revealed mechanisms of ANS dysfunction in models of dysautonomia, which might be expanded to dysautonomia in other diseases to develop effective treatments. The models we built cover several components of the ANS, and are powerful tools to comprehensively study human ANS mediated neural disorders in future.