Poster Presentation 6th Annual Meeting for Australasian Society for Stem Cell Research 2013

Identification of microRNAs regulated by Twist-1 which are important for mesenchymal stem cell growth and osteogenic differentiation (#110)

Esther Camp 1 2 , Sandra Isenmann 1 2 , Dimitrios Cakouros 1 2 , Stan Gronthos 1 2
  1. Adelaide Medical School, University of Adelaide, Adelaide, S.A, Australia
  2. Centre for Stem Cell Research, Robinson Institute, University of Adelaide, Adelaide, SA, Australia

Human bone marrow derived mesenchymal stem cells (MSCs) are a stem/progenitor cell population with the ability to differentiate into different cell types of the mesenchymal germ layer 1. The proliferation and differentiation of MSCs is tightly regulated by multiple pathways that lead to the activation of specific transcription factors. Among the transcription factors involved, the basic helix-loop-helix (bHLH) transcription factor Twist-1, is a key regulator of MSC self-renewal, proliferation and lineage commitment 2. However, the molecular mechanisms by which it does this are not completely understood.

An increasing number of studies have demonstrated the involvement of microRNAs (miRNAs) in the proliferation and or osteogenic differentiation of MSCs. Twist-1 has been shown to regulate the miRNA cluster miR-199/214 during development 3. To date, no MSC specific miRNAs regulated by Twist-1 have been identified. In this study we set out to identify Twist-1 miRNA targets involved in MSC proliferation and osteogenic differentiation. To do this, we compared the miRNA expression profile of MSCs which express endogenous levels of Twist-1 to MSCs which have enforced expression of Twist-1 during cell culture conditions or undergoing osteogenic differentiation. We have identified a number of miRNAs that are differentially expressed between the two MSC lines. This includes miRNAs already known to play a role in MSC maintainance and or osteogenesis such as the miR-30 family, let-7 family, miR-21 and miR-100, as well as a number of miRNAs not previously known to be involved in these processes.

We are currently performing knock-down and over-expression studies of selected miRNAs, and the genes which these miRNAs target, to determine their function during MSC proliferation and or differentiation. This study is the first to identify Twist-1 regulated miRNAs important for MSC maintenance, proliferation and osteogenic differentiation and will help us to better understand the processes that mediate MSC growth and fate determination.

  1. Gronthos S, Zannettino AC, Hay SJ, Shi S, Graves SE, Kortesidis A, Simmons PJ 2003 Molecular and cellular characterisation of highly purified stromal stem cells derived from human bone marrow. J Cell Sci 116(9):1827-35.
  2. Isenmann S, Arthur A, Zannettino AC, Turner JL, Shi S, Glackin CA, Gronthos S 2009 TWIST Family of Basic Helix-Loop-Helix Transcription Factors Mediate Human Mesenchymal Stem Cell Growth and Commitment. Stem Cells (27):2457-2468.
  3. Lee Y-B, Bantounas I, Lee D-Y, Phylactou L, Caldwell M A, Uney JB 2009 Twist-1 regulates the miR-199a/214 cluster during development. Nucleic Acids Research 37 (1):123-128.