Many neuropsychiatric disorders such as autism, epilepsy, schizophrenia, and intellectual disability start early in life and often contribute to a lifetime disability. The rising incidence of these disorders is expected to cause a major public health challenge in the coming decades. Despite the impending challenge, drug development for these disorders is facing a crisis; most major pharmaceutical companies have reduced their investment in psychiatric drug development because of a high failure rate. Limitations associated with animal models and a dearth of druggable biological targets, coupled with poor access to the living human brain for dynamic observation and experimentation all conspire to impose an enormous challenge of finding effective psychiatric drugs. Recent advances in human induced pluripotent stem cells (hiPSC) have made it possible to create a patient-specific brain-like neural tissue (referred to as `cerebral organoid') that displays an architecture and neural network activity resembling that of human tissue. These cerebral organoids (CO) offer researchers an exciting opportunity to investigate disease mechanisms responsible for the development of neuropsychiatric disorders in humans. We propose in this project to link CO with a tissue-engineered blood vessel (BV) and their blood-brain barrier (BBB) interface to form a cerebral microphysiological system (CMPS). There is documented anatomical parallelism between vessel and nerve patterning and development, and it has also emerged that neuron and vessel specification, growth, navigation, and survival share many molecular pathways. The same signaling pathways also play a critical role in the crosstalk between nerves and vessels during the injury repair process in adult brain. Therefore, it is important to understand the interactions between the CNS and the vascular system under physiological and pathophysiological conditions. We propose to use two well-defined genetic lesions, the 22q11.2 deletion syndrome (22q11.2DS or DiGeorge syndrome) and the Proteus syndrome, that affect both the CNS and vascular systems for the development and validation of CMPS. The proposed CMPS, if successful, will offer a powerful platform to screen neuropsychiatric drugs as well as to develop novel neuropsychiatric treatment strategies that target the shared mechanisms between the CNS and the vascular system.
Psychiatric drug development has a high failure rate because of inadequate animal models and poor access to the living human brain for dynamic observation and molecular investigations. We propose to generate human induced pluripotent stem cell- based cerebral organoids that can resemble the structure and functions of a human brain tissue. Using DiGeorge Syndrome and Proteus Syndrome as our disease models, we will develop a cerebral microsphysiological unit for disease modeling and psychiatric drug screening.
