Abstract 3588: Induced Pluripotent and Fetal Derived Neural Stem Cells Differ in Chemokine and Receptor Expression.

Abstract

Introduction: Cell based therapies have shown a considerable ability to improve functional outcome when administered after experimental stroke. Intra-arterial (IA) cell transplantation has been shown to be a valuable alternative transplantation method for cell treatment. The success of IA therapy depends on the targeted homing and subsequent migration of cells to the injured brain area. This process is reliant on neural stem cell (NSC) expression of chemokines and their receptors. Understanding the differences in cell expression of these molecules and the resulting differences in chemotaxis will help identify ideal cell types for transplantation. Previously, we compared mRNA from human and mouse NSCs and found that only a 10% overlap in chemokine expression. We wanted to determine if there are also variations between different cell types from the same species. We compared NSCs obtained from induced pluripotent stem cells (iPS NSCs), to fetal NSCs (F NSC). We used RT-qPCR, in vitro cell migration, and quantification of cell secretion to compare chemokine and ligand expression in F NSCs and iPS NSCs. Methods: Secondary neurospheres originating from FVB mice were generated from either fetal primary NSCs from E17.5 mice (F NSC), or derived by transducing neurospheres originating from E3 mice with Oct4 (iPS NSC). Cells were grown as neurospheres in growth media treated with EGF and FGF. RT-qPCR was performed on extracted RNA using microarray technology for chemokine receptors and ligands. Luminex immunological assay was completed to assess secreted cytokines and inflammatory proteins. The Boyden chamber migration assay was used to determine migration to SDF-1 or MCP-1 at varying concentrations. Results: RNA expression was detected for 58% of the factors assessed. F NSCs alone expressed 6% (e.g. mmp2, Cxcl10), iPS NSCs alone expressed 16% (e.g. CCL2, CCL7, LIF), and both iPS NSCs and F NSCs expressed 20% (e.g. BDNF, HIF1a, CXCR4) of the detected factors. We assessed 26 secreted proteins, 73% occurred at detectable levels, of these 74% were expressed more highly in F NSCs than in iPS NSCs, including, il-1α, CCL3, CCL5, TNF-α, and VEGF; iPS NSCs secreted higher levels of MCP3, Il-3, and substantially more MCP-1 (113.7 ± 1.44 vs 52.78 ±4.221 pg/ml). iPS NSCs also had a higher migratory response to MCP-1 than F NSCs did (p < 0.001). Cell migration to SDF-1 did not differ between cell types (p = 0.905). Conclusions: Several chemokines and their receptors were differentially expressed in mouse iPS and F NSCs. These differences may result in variations in the NSC response to the ischemic brain. The profile of chemokine and chemokine receptor expression on NSCs should be strongly considered when selecting cell types for post stroke treatment.