Publication Date:
2012-11-16
Description:
Abstract 3459 The different intra- and extracellular constituents of the hematopoietic stem cell (HSC) niche in the human bone marrow are tightly regulated and of momentous importance for various properties of HSCs. Some of these are regulated through β1-Integrins (CD29) which therefore dramatically influence HSC and mesenchymal stromal cell (MSC) interaction in the niche. Important regulators within these cells are microRNAs (miRNAs). These small, non-coding RNAs control the expression of around two-thirds of the human protein-coding genes. One of these miRNAs, miR-134, previously referred to be a “brain-specific” miRNA was shown to be highly expressed in MSCs in tissue-studies conducted by our group. Since the central nervous system was recently shown to be closely connected to the regulation of HSCs and MSCs, we asked whether miR-134 which has several conserved binding seed-match sequences within the 3'UTR of β1-Integrin, regulates MSC mediated properties in the bone marrow niche. Screening of human MSC cell lines (n=4) by western blotting revealed highest β1-Integrin expression in SCP-1 cells. Transfection of SCP-1 with either siRNA directed against β1-Integrin (siCD29) or pre-miRNA-134 (pre134) revealed a downregulation of β1-Integrin at the mRNA level only in siRNA transfected cells, p=0.01. In contrast, at the protein level, as measured by western blot and FACS analysis, p=0.002, β1-Integrin was downregulated by siCD29 as well as by pre134, indicating a miRNA-specific action of repression. Confirmatory, the 3'UTR of β1-Integrin, which contains several putative binding sites for miR-134, was cloned into a pMiRReporter vector and luciferase activity was measured after cotransfection with pre134. The luciferase activity was significantly reduced in pre134 transfected cells [1.80 ± 0.46 (preCo) vs. 0.99 ± 0.49 (pre134); p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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