Year 2

The goal of this proposal is to determine the isoform-specific effects of apolipoprotein (apo) E on the development of induced pluripotent stem (iPS) cells into functional neurons both in vitro and in mice. Toward this goal, we have made significant progress in the past year, as summarized below.

First, We developed human iPS cells from skin fibroblasts of individuals with different apoE genotypes. We are fully characterizing these human iPS cell lines.

Second, We are establishing neural stem cell (NSC) lines from human iPS cells with different apoE genotypes. Some of the NSCs have been maintained in monolayer cultures for many generations. These NSCs will be used to study the effects of apoE isoforms on neuronal development in vitro in cultures and in vivo in mice.

Finally, we demonstrated that mouse apoE4-NSCs generated significantly fewer total neurons and fewer GABAergic interneurons than mouse apoE3-NSCs in culture. Thus, the detrimental effects of apoE4 on neurogenesis and GABAergic interneuron survival, as we observed in vivo in apoE4 knock-in mice (Li G. et al. Cell Stem Cell, 2009, 5:634-645), are recapitulated in cultures of mouse iPS cell–derived NSCs in vitro.