Determining the Pathogenesis of Dystonia in Reprogrammed Human Neurons
Abstract
The major purpose of this project is to develop novel cellular models for dystonia research and examine the alterations of dystonia neurons at cellular and molecular levels. Dystonia is the third most common movement disorder (behind Essential Tremor and Parkinson s Disease) characterized by uncontrolled muscle contractions causing abnormal movements, postures, and pain. There are as many as 250,000 patients have dystonia in the U.S. alone (American Association of Neurological Surgeons). It can affect from young children to adults of all races and ethnicities. In particular, Veterans are at higher risk due to the frequent occurrence after head trauma and potentially irreversible side effects of medications used to treat post-traumatic stress disorder (PTSD). However, there is still no specific therapy available for this potentially disabling condition due to unclear disease mechanisms. The clinical characteristics and underlying causes of dystonia are very different. One type of childhood-onset dystonia called DYT1 dystonia represents the most frequent and severe form of hereditary dystonia. It is caused by a loss-of-function mutation in DYT1 (torsin A) gene under a heterozygous background (one copy of this gene is mutated and the other copy is normal). Most pathological mechanisms of dystonia already known so far largely came from the studies of DYT1 dystonia, particularly from studies in gene-knockout mouse models. Unfortunately, mice with the identical DYT1 (torsinA) mutation as a heterozygote failed to show any disease syndromes, suggesting the substantial differences at pathological mechanisms between mouse models and human patients. Thus, it is critical to investigate the disease mechanisms using patient’s samples directly. However, the limited access to patient neurons and the lack of in vitro human cellular models greatly impede the progress of dystonia research. This project aims to develop novel cellular models through reprogramming human neurons from fibroblasts of dystonia patients. Fibroblast cells can be prepared from skin tissues and are usually commercially available from cell banks. First, human neurons will be generated from fibroblasts of dystonia patients and healthy controls. Reprogramming factors will be delivered into fibroblasts and gradually convert fibroblasts into neurons. The neuron identity, maturation, and functions will be confirmed by verified analysis. Second, these patient-specific neurons and healthy controls will be closely studied at cellular and molecular levels, including the neurodevelopment, survival, electrophysiology, nuclear morphology, and nuclear transport. The long-term goals of this project are to identify dysregulated factors in dystonia neurons and to seek molecular targets for intervention therapy. Expected results emanating from this study will advance our understanding of the disease mechanisms. The establishment of novel cellular models will greatly promote dystonia research. Human neurons directly generated from patient fibroblasts will overcome the long-standing limitations in dystonia research, the shortage of patient’s neuron samples, and the lack of in vitro cell systems. These patient-specific neurons generated by the direct conversion approach do not alter the levels of gene expression (such as overexpress or completely knockout mutant genes) and make dystonia study in a more human-disease-relevant manner. Most importantly, generation of large amount of patient-specific neurons from dystonia patients makes it possible to decipher the disease mechanisms via biochemical approaches, such as identify molecular targets for drug development.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010186
Entities
People
- Baojin Ding
Organizations
- United States Army
- University of Louisiana at Lafayette