The proposed study is designed to determine how distinct subsets of melanocyte stem cells (MSCs) we have identified are regulated and maintained in the stem cell state and contribute to neural crest-derived cell regeneration. The rationale for the study is based upon our discovery that MSCs not only populate a region of the murine hair follicle (HF) termed the bulge, also the site of keratinocyte stem cells (KcSCs) of the HF, but also the secondary hair germ (SHG), a transient structure at the base of the telogen, or resting, HF adjacent to the dermal papilla. Our laboratory has developed methods to separate and study these two cell subsets in the viable state using a combination of a unique transgenic mouse system and fluorescence-activated cell sorting (FACS).The objectives of our studies are to discover specific markers of these stem cell subsets and to determine whether CD34+ MSCs in mice, and their cellular analogs in humans, can regenerate functional glial and neuronal cells, as suggested by preliminary data. We will also determine both in vitro and in vivo whether the CD34+ MSC subset, which exhibits an expanded developmental potential compared to CD34- MSCs, can regenerate neural crest- derived glial and neuronal cells. Information obtained from murine experiments will be used to identify comparable stem cell populations from human skin. These studies will be accomplished a unique, bitransgenic mouse line we have developed, Dct-H2BGFPki, in combination with the FACS facility and other core resources associated with my research laboratory located in the Department of Biochemistry and Molecular Biology at the University of Maryland School of Medicine. The results of these studies should have a positive impact on the health care of Veterans. Our discovery that the CD34+ MSC subset selectively expresses glial and neuronal markers may provide a strategy for using cells easily obtained from human skin to be used to support Veteran recovery from neurological injury and neurodegenerative disease.
Regenerating nerves and their supporting cells using easily-obtained stem cells from human skin could alleviate Veteran burden of disease from both traumatic and chronic degenerative neurological disease. In this research study, a type of melanocyte stem cell (MSC) which has the ability to express nervous system proteins will be studied. We will evaluate whether these easily-obtained MSCs from mouse skin are capable of producing functional neurons and their glial supporting cells. We will determine whether similar cells present in human skin also share that ability. Identifying mechanisms that regulate the regenerative properties of MSCs will facilitate the isolation and generation of comparable human cells that can be introduced into injured and degenerating neurons to provide regenerative support to these tissues and alleviate the burden of related diseases.