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Biomedical subjects

Jingli Cai

Publications and source records attributed to Jingli Cai.

23 records · Page 2Linked to original sources

Microarray analysis of selected genes in neural stem and progenitor cells.

To access and compare gene expression in fetal neuroepithelial cells (NEPs) and progenitor cells, we have used microarrays containing approximately 500 known genes related to cell cycle regulation, apoptosis, growth and differentiation. We have identified 152 genes that are expressed in NEPs and 209 genes expressed by progenitor cells. The majority of genes (141) detected in NEPs are also present in progenitor populations. There are 68 genes specifically expressed in progenitors with little or no expression in NEPs, and a few genes that appear to be present exclusively in NEPs. Using cell sorting, RT-PCR, in situ hybridization or immunocytochemistry, we have examined the segregation of expression to neuronal and glial progenitors, and identified several that appeared to be enriched in neuronal (e.g. CDK5, neuropilin, EphrinB2, FGF11) or glial (e.g. CXCR4, RhoC, CD44, tenascin C) precursors. Our data provide a first report of gene expression profiles of neural stem and progenitor cells at early stages of development, and provide evidence for the potential roles of specific cell cycle regulators, chemokines, cytokines and extracellular matrix molecules in neural development and lineage segregation.

Animals↗

Stem cell and precursor cell therapy.

Strategies for cell replacement therapy have been guided by the success in the hematopoietic stem cell field. In this review, we discuss the basis of this success and examine whether this stem cell transplant model can be replicated in other systems where stem cell therapy is being evaluated. We conclude that identifying the most primitive stem cell and using it for transplant therapy may not be appropriate in all systems. We suggest alternative strategies such as progenitor cell replacement, inductive factors, bioengineering organs, in utero transplants, or any approach that takes advantage of the unique properties of the tissue and the stem cell type which, are more likely to provide effective functional replacement.

Animals↗

Identifying and tracking neural stem cells.

Hematopoietic stem cells, unlike neural stem cells, can be readily identified and isolated from developing and adult cell populations using positive and negative selection criteria. Isolating stem cells and progenitor cells from neural tissue has been more difficult because of difficulties in separating cells in solid tissue, the limited numbers of stem cells that persist in the adult, and the paucity of rigorously characterized markers. Nevertheless, strategies that have worked successfully in hematopoietic stem cell isolation can be adapted to isolate multiple classes of stem and progenitor cells from neural tissue. Neural stem cells also share cellular and molecular properties with other stem cell populations that may serve as surrogate identifiers of multipotentiality. Such potential markers are described. Unlike hematopoietic stem cells, tracking neural cells after transplantation is both necessary and more difficult. It will therefore be necessary to develop invasive and non-invasive strategies to follow transplanted cells and develop useful quantifiable readouts. Some potential strategies are described and current results are discussed.

Cell Separation↗

Distinguishing features of progenitor cells in the late embryonic and adult hippocampus.

Adult neurogenesis occurs within the subgranular layer of the hippocampal dentate gyrus. In this study, we examined dividing cells in the late embryonic and adult rat hippocampus to identify distinguishing characteristics and potential neural stem cell population(s), as identified by the putative neural stem cell markers FGFR4 and Sox1. In embryonic hippocampal cells in primary culture, basic fibroblast factor caused cell proliferation, increased telomerase activity and upregulation of FGFR4 mRNA. In both the embryonic and adult brains, proliferating cells express Sox1, as well as markers for neuronal- and glial-restricted precursors. However, the cell markers associated with cells expressing proliferative cell nuclear antigen (PCNA) and Sox1 differed between late embryonic and adult hippocampus, suggesting that there are important differences between adult and embryonic neurogenesis.

Animals↗

Characterization of progenitor-cell-specific genes identified by subtractive suppression hybridization.

We have utilized subtractive suppression hybridization (SSH) to identify differentially expressed genes present in either neuroepithelial (NEP) cells or glial restricted precursor (GRP) cells. Eighteen clones enriched in GRP cells and 28 in NEP cells were identified. Five of the GRP-specific clones (tenascin C, cystatin C, GABA transporter 3, extracellular matrix molecule 2 and H2-4) were characterized further, and their glial specificity was confirmed by RT-PCR, in situ hybridization and immunocytochemistry. H2-4 (an expressed sequence tag) was shown to be part of chondroitin sulfate proteoglycan 3. Overall, our results show that SSH can be used to identify lineage- and stage-specific markers and that extracellular matrix molecules likely play important roles in the migration and differentiation of GRPs.

Animals↗