High throughput transcriptome profiling of lithium stimulated human mesenchymal stem cells reveals priming towards osteoblastic lineage

PLoS One. 2013;8(1):e55769. doi: 10.1371/journal.pone.0055769. Epub 2013 Jan 30.

Abstract

Human mesenchymal stem cells (hMSCs) present in the bone marrow are the precursors of osteoblasts, chondrocytes and adipocytes, and hold tremendous potential for osteoregenerative therapy. However, achieving directed differentiation into osteoblasts has been a major concern. The use of lithium for enhancing osteogenic differentiation has been documented in animal models but its effect in humans is not clear. We, therefore, performed high throughput transcriptome analysis of lithium-treated hMSCs to identify altered gene expression and its relevance to osteogenic differentiation. Our results show suppression of proliferation and enhancement of alkaline phosphatase (ALP) activity upon lithium treatment of hMSCs under non-osteogenic conditions. Microarray profiling of lithium-stimulated hMSC revealed decreased expression of adipogenic genes (CEBPA, CMKLR1, HSD11B1) and genes involved in lipid biosynthesis. Interestingly, osteoclastogenic factors and immune responsive genes (IL7, IL8, CXCL1, CXCL12, CCL20) were also downregulated. Negative transcriptional regulators of the osteogenic program (TWIST1 and PBX1) were suppressed while genes involved in mineralization like CLEC3B and ATF4 were induced. Gene ontology analysis revealed enrichment of upregulated genes related to mesenchymal cell differentiation and signal transduction. Lithium priming led to enhanced collagen 1 synthesis and osteogenic induction of lithium pretreated MSCs resulted in enhanced expression of Runx2, ALP and bone sialoprotein. However, siRNA-mediated knockdown of RRAD, CLEC3B and ATF4 attenuated lithium-induced osteogenic priming, identifying a role for RRAD, a member of small GTP binding protein family, in osteoblast differentiation. In conclusion, our data highlight the transcriptome reprogramming potential of lithium resulting in higher propensity of lithium "primed" MSCs for osteoblastic differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaline Phosphatase / metabolism
  • Bone Marrow Cells / cytology
  • Bone Marrow Cells / drug effects
  • Bone Marrow Cells / metabolism
  • Cell Culture Techniques
  • Cell Differentiation* / drug effects
  • Cell Differentiation* / genetics
  • Cell Nucleus / metabolism
  • Cell Proliferation
  • Enzyme Activation / drug effects
  • Gene Expression Profiling*
  • Gene Expression Regulation / drug effects
  • Gene Knockdown Techniques
  • Glycogen Synthase Kinase 3 / antagonists & inhibitors
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Lithium / pharmacology
  • Mesenchymal Stem Cells / cytology*
  • Mesenchymal Stem Cells / drug effects
  • Mesenchymal Stem Cells / metabolism*
  • Molecular Sequence Annotation
  • Osteoblasts / cytology*
  • Osteogenesis / drug effects
  • Osteogenesis / genetics
  • Protein Transport / drug effects
  • Reproducibility of Results
  • Transcription, Genetic / drug effects
  • Transcriptome*
  • Wnt Signaling Pathway / drug effects
  • beta Catenin / metabolism

Substances

  • beta Catenin
  • Lithium
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3
  • Alkaline Phosphatase

Grants and funding

This work was supported by funding from Defence Research and Development Organisation, Ministry of Defence, Government of India. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.