Localized Growth Factors Effects on Myelination by hESC Derived Oligodendrocytes in a Novel Microfluidic Platform

In the central nervous system (CNS), the loss of protective myelin sheath surrounding axons, known as demyelination, is a major cause of sensory and motor function deficits in diseases such as multiple sclerosis (MS) and trauma such as spinal cord injury (SCI). Unfortunately, the body's endogenous oligodendrocyte (OLs) and OL progenitor cells (OPCs) are unable to remyelinate axons sufficiently to overcome the damage to axons caused by such diseases and injuries. The capacity of human embryonic stem cells (hESCs) for unlimited proliferation and to differentiate into a wide variety of cell types makes them a promising target to enhance remyelination through hESC-derived OPCs cell replacement therapy. Further, medical science cannot currently enhance myelination therapeutically because mechanisms regulating the process of myelination are not well understood. Although there is growing knowledge about the various factors involved in OL lineage proliferation, survival, and differentiation OLs, little is known about the molecular control of the myelination process itself.

The goals of this research are a) to establish the technique of in vitro myelination and b) to identify the role of growth factors in myelination through the use of embryonic stem cell derived OLs in a novel compartmentalized microfluidic co-culture platform. Our experiments will utilize this microfabricated co-culture platform that more closely resembles in vivo myelination where unlike conventional mixed culture experiments, OLs and axons are separated from neuronal soma and dendrites. Using this platform, we will localize the cellular site of action through which growth factors act to enhance myelination and promote OL maturation. Here, we hypothesize that human embryonic stem cells derived OPCs (hESC-OPCs) will differentiate into OLs and myelinate CNS axons in the novel compartmentalized microfluidic co-culture platform. Furthermore, we will determine the site of action of four growth factors (BDNF, NT-3, CNTF, and LIF) that enhance the differentiation of hESC-OLs and myelination of CNS axons.