miR-124 and miR-128 differential expression in bone marrow stromal cells and spinal cord-derived neural stem cells

BACKGROUND: MicroRNA (miRNA) expression in stem cells provides important clues for the molecular mechanisms of stem cell proliferation and differentiation. Bone marrow stromal cells and spinal cord-derived neural stem cells exhibit potential for neural regeneration. However, miRNA expression in these cells has been rarely reported. OBJECTIVE: To explore differential expression of two nervous system-specific miRNAs, miR-124 and miR-128, in bone marrow stromal cells and spinal cord-derived neural stem cells. DESIGN, TIME AND SETTING: An In vitro, cell biology experiment was performed at the Department of Biotechnology, Shanxi Medical University from June 2008 to June 2009. MATERIALS: TaqMan miRNA assays were purchased from Applied Biosystems. METHODS: Rat bone marrow stromal cells were isolated and cultured using the whole-bone marrow method, and rat spinal cord-derived neural stem cells were obtained through neurosphere formation. TaqMan miRNA assays were used to measure miR-124 and miR-128 expression in bone marrow stromal cells and spinal cord-derived neural stem cells. MAIN OUTCOME MEASURES: Morphology of bone marrow stromal cells and spinal cord-derived neural stem cells were observed by inverted microscopy. Expression of the neural stem cell-specific marker, nestin, the bone marrow stromal cell surface marker, CD71, and expression of miR-124 and miR-128, were detected by real-time polymerase chain reaction. RESULTS: Cultured bone marrow stromal cells displayed a short fusiform shape. Flow cytometry revealed a large number of CD71-positive cells (> 95%). Cultured spinal cord-derived neural stem cells formed nestin-positive neurospheres, and quantitative detection of miRNA demonstrated that less miR-124 and miR-128 was expressed in bone marrow stromal cells compared to spinal cord-derived neural stem cells (P < 0.05). CONCLUSION: Bone marrow stromal cells and spinal cord-derived neural stem cells exhibited differential expression of miR-124 and miR-128, which suggested different characteristics in miRNA expression.