Research

Modeling neurological disorders using induced pluripotent stem cells (iPSCs) and organoid culture

Movement disorders comprise an important subset of neurological disorders in terms of prevalence, morbidity and ensuing disability. Movement disorders are disorders of the nervous system typically affecting the basal ganglia and its connections, that result in either an abnormal increase (hyperkinetic) or decrease (hypokinetic) in movement.

We initiated a program, entitled” Indian Collaborative Research Network on Wilson's Disease (iCROWD) Understanding molecular genetics towards better diagnosis and therapy” as a primary forum and network to this end. A pilot network of over 35 clinicians from over 20 centres across the country have already been established.

Through this approach, diagnosis is provided for cases, which present with a known and classified variant. For novel variants and genes identified, in-depth assays would be established including in-vitro. A subset of the putative novel variations would be modeled in appropriate models such as induced pluripotent stem cells (iPSC) lines. This would permit obtaining patient-specific biological data and finally one could use that to customize patient-specific clinical solutions. Genetic engineering to create iPSC lines and corrections by the CRISPR-Cas9 system also provides a new opportunity to apply these models for the discovery of novel therapeutics as well as to reposition existing drugs for new indications in Wilson’s diseases (WD) and Dystonia. Our lab has collected human blood samples from healthy individuals as well as Wilson's disease, Parkinson’s disease, and Dystonia patients, and reprogrammed them into induced pluripotent stem cells (iPSCs). We use genome-editing techniques such as CRISPR/Cas9 to create isogenic cell lines to facilitate the assessment of phenotypic consequences of disease-associated genetic variants. These iPSCs are then differentiated into major brain cell types including motor neurons, astrocytes, and microglia that can be used for a number of basic and applied research purposes. For example, we can use this system to examine how specific gene perturbations affect neuro WD-like pathology directly in human neurons and glia, while at the same time screening libraries of protein kinase inhibitors to determine potential therapeutic candidates. Increasingly sophisticated next-generation sequencing technique allows us to identify the disease-specific genetic variants and culture techniques to evaluate how disease pathology affects each of the different cell types populating the brain and liver. In “mini-brain and liver organoid” cultures, we can examine hepatocytes cell function, neuronal and glial activity, and examine relevant disease phenotypes such as protein aggregation, neuronal connectivity, synapse loss, and deposition of copper.