Human pluripotent stem cell (hPSC) technology has advanced to the point where derivation of several therapeutic cell types can be achieved using ‘bench-top’ protocols; however, clinical translation requires protocols that can be scaled-up to rapidly and efficiently generate distinct cell phenotypes. Additionally, therapeutic applications remain limited by a lack of methodologies for in vitro tissue formation, which entails generating cell aggregates containing discrete spatial domains of diverse cellular phenotypes in biomimetic orientations.
My research aims to overcome this limitation by elucidating how factors of the cellular microenvironment work synergistically to regulate hPSC fate and utilizing this information to rationally engineer materials and methods for generating higher-order tissue structures in vitro that accurately recapitulate human anatomy and physiology.
Although we are broadly interested in generating numerous tissues within the human body, our research is presently focused on in vitro engineering of tissues representative of the human central nervous system and vasculature. Results from this research could yield humanized tissue platforms that could serve as invaluable in vitro models for drug discovery and investigating neurodegenerative diseases, e.g. Amyotrophic Lateral Sclerosis or Spinal Muscular Atrophy, and as a template for engineering implantable tissues.
Scalable and clinically translatable protocols for deriving regional neural phenotypes from hSPCs
During development, the central nervous system is patterned with enormous levels of cellular phenotype diversity that arises at distinct anatomical regions. For example, motor neurons of the forebrain have different gene and protein expression profiles than those that populate the abducens nucleus in your hindbrain or those which project to your arms. In turn, each separate regional motor neuron pool displays differential susceptibility to neurodegenerative disorders, e.g. Amyotrophic Lateral Sclerosis (a.k.a. Lou Gehrig’s disease). To gain insight into this diversity and produce potential cellular therapeutics that display regionally matched phenotypes, and thereby could facilitate enhanced regeneration of tissue function, we are developing scalable and clinically translatable protocols to derive region-specific neural stem cells and derivatives from hPSCs.
Contacts: Nisha Iyer
The stem cell-biomaterial interface
Standard cell culture has many limitations; one of those being a lack of spatiotemporal control over the cell-culture substrate interface. In this research thrust, we are engineering biomaterials at the micro-to-nanoscale that can serve as precisely defined culture substrates that can be ‘programmed’ to control hPSCs and their derivative neural tissues in a spatiotemporal manner. To generate such substrates, we have developed both novel chemistries and microcontact printing modalities. Such substrates will be critical to control in vitro morphogenesis of hPSC-derived neural tissues.
Contacts: Gavin Knight and Alireza Aghayee
Scalable Manufacture of Biomimetic 3D Neural Organoids
While hPSC-derived cell therapies are now reaching clinical trials, hPSCs greatest impact continues to be providing novel, biomimetic experimental platforms for investigating human development, biology, physiology, and disease. Human PSC-derived models can be personalized to patients via use of induced pluripotent stem cells (iPSCs), and they avoid confounding differences that exist between rodents and humans. Recently, 3-D aggregates of neurally differentiating hPSCs were observed to spontaneously morph in vitro into organotypic masses, a.k.a. cerebral organoids, containing diverse brain tissues. Discovery of this innate emergent behavior raises the possibility that human CNS morphogenesis can be engineered ex vivo to generate diverse brain and spinal cord tissues with biomimetic structure, cellular composition, cytoarchitecture— micro-to-millimeter scale spatial organization of cell phenotypes—, and even function via biomimetic neuronal circuits. However, to realize this possibility, the currently spontaneous and random organoid morphogenesis process must become instructed and standardized, a prerequisite for translation of human neural organoids as clinically predictive models and transplants. In pursuit of this goal, we meld neurodevelopmental and hPSC biology with engineered biomaterial platforms to create novel methodologies for instructing ex vivo, 3D morphogenesis of human neural tissues.
Contacts: Carlos Marti-Figueroa