Region-specific differentiation of neural tube-derived neuronal restricted progenitor cells after heterotopic transplantation

Abstract

Irrespective of the region of isolation NRP cells share several properties: an ability to divide, the expression of polysialated neural cell adhesion molecule, the expression of neuronal markers such as type III ␤-tubulin and microtubule-associated protein 2 (MAP-2), and an inability to generate glial derivatives in conditions in which other precursors readily generate astrocytes and oligodendrocytes. The neuronal lineage commitment of the NRPs seems immutable and is in contrast to progenitor populations described by Roy et al. (24), where oligodendrocyte precursors in vitro generated a small number of type III ␤-tubulin-positive cells.Despite their overall similarities, differences between neural progenitor cells isolated from different brain regions exist (reviewed in ref. 9). For example, progenitors from the hippocampus, but not from the cerebellum or midbrain, produce hippocampal pyramidal neurons. Likewise, Luskin and colleagues (25) have noted that neurons derived from the anterior forebrain subventricular zone (SVZa) undergo GABAergic differentiation when transplanted into the striatum. These and other results raise the possibility that the restriction in developmental potential arises early and cannot be reversed. Multiple classes of NRPs distinguished on the basis of their ability to generate specific subclasses of neurons may exist.In this study, the ability of spinal cord NRP cells to migrate and differentiate after their transplantation into the neonatal SVZa was examined and compared with endogenous and homotypically transplanted SVZa NRP cells. Our results show that spinal cord NRP cells are restricted to generating neurons in vivo. NRPs, however, migrate extensively and incorporate into different brain regions, and subsets of cells synthesize cholinergic, glutaminergic, and GABAergic neurotransmitters. Spinal cord NRPs differ from SVZa-derived NRPs in their migration and differentiation, indicating that cell intrinsic mechanisms play an important role in regulating differentiation. Materials and MethodsIsolation and Labeling of NRP and GRP Cells. Cells were isolated as described (12). Immunoselected cells were labeled by using an enhanced green fluorescent protein (GFP) retroviral construct (gift from Ray White, University of Utah). The construct was packaged by using the Phoenix cell line (gift from Gary Nolan, Stanford University, Stanford, CA). Viral supernatant was collected from infected cells grown in neuroepithelial basal medium. GFP expression in infected cells (10%) was evident within 48 h in vitro, and its expression persisted for at least 10 days.Transplantation of GFP-Labeled NRP and GRP Cells. The procedure described by Luskin and coworkers (16, 25) was used with slight modifications to transplant cells into the right SVZa of postnatal day 1 rat pups. About 3 l of the GFP-labeled NRP or GRP cell suspension (approximately 3 ϫ 10 4 cells) was injected into the SVZa. The needle was left in position for approximately 3 min and gradually withdrawn, the skull flap was repositioned, and the...

Cancerous stem cells can arise from pediatric brain tumors

“…The data shown in Fig. 5, which is published as supporting information on the PNAS web site, demonstrate that the transplanted cells incorporate into the brain, have the characteristics of migrating neurons (38), differentiate into neuronal and glial elements, and continue to divide as demonstrated by expression of Ki-67, a marker of cycling cells (39).…”

Functional Integration of Embryonic Stem Cell-Derived NeuronsIn Vivo

“…However, after retrieval from the slice culture and further in vitro propagation, they induce the ventral forebrain marker Dlx2 (Hitoshi et al, 2002). Data from in vivo transplantation experiments in the neonatal and adult brain indicate that heterotopically grafted primary neural precursors fail to adopt site-specific phenotypes (Zigova et al, 1998;Yang et al, 2000;Turner and Shetty, 2003). In contrast, cross-transplantation of cells from or into areas exhibiting postnatal neurogenesis (i.e., hippocampus, olfactory bulb, and cerebellum) has yielded evidence for site-specific differentiation, suggesting that local guidance cues might be maintained in these regions (Renfranz et al, 1991;Vicario-Abejó n et al, 1995;Suhonen et al, 1996).…”

Direct Conversion of Human Fibroblasts into Neuronal Restricted Progenitors

“…When injected into the subventricular zone, NRPs can migrate extensively and incorporate with the different regions of the brain to differentiate into various subtypes of neurons, contributing to brain plasticity and repair (19). However, the traditional acquisition of well purified NRPs through isolation from normal nervous tissue is difficult and cumbersome (18,22), which makes it impossible to acquire sufficient cells for clinical and commercial application.…”

“…In neurogenesis, another major type of cell, called neuronal restricted progenitor (NRP, also known as neuroblast), which has the abilities of proliferation and migration through the rostral migratory stream in the nervous system (18,19), can develop into neurons, rather than glial cells or other cell types, in vivo and in vitro (20,21). When injected into the subventricular zone, NRPs can migrate extensively and incorporate with the different regions of the brain to differentiate into various subtypes of neurons, contributing to brain plasticity and repair (19).…”