Glycosaminoglycans enhance osteoblast differentiation of bone marrow derived human mesenchymal stem cells Smitha Mathews 1 , Suja Ann Mathew 1 , Pawan Kumar Gupta 1 , Ramesh Bhonde 1 and Satish Totey 2 * 1 Manipal Institute of Regenerative Medicine, (Manipal University),10 Service Road, Domlur, Bangalore-560071, India 2 Kasiak Research Pvt Ltd, 31, Makers Chamber VI, Nariman Point, Mumbai-400021, India Abstract Extracellular matrix plays an important role in regulating cell growth and differentiation. The biomi- metic approach of cell-based tissue engineering is based on mirroring this in vivo micro environment for developing a functional tissue engineered construct. In this study, we treated normal tissue culture plates with selected extracellular matrix components consisting of glycosaminoglycans such as chondroitin-4-sulphate, dermatan sulphate, chondroitin-6-sulphate, heparin and hyaluronic acid. Mes- enchymal stem cells isolated from adult human bone marrow were cultured on the glycosaminoglycan treated culture plates to evaluate their regulatory role in cell growth and osteoblast differentiation. Although no significant improvement on human mesenchymal stem cell adhesion and proliferation was observed on the glycosaminoglycan-treated tissue culture plates, there was selective osteoblast differentiation, indicating its potential role in differentiation rather than proliferation. Osteoblast differentiation studies showed high osteogenic potential for all tested glycosaminoglycans except chondroitin-4-sulphate. Osteoblast differentiation-associated genes such as osterix, osteocalcin, integrin binding sialoprotein, osteonectin and collagen, type 1, alpha 1 showed significant upregulation. We identified osterix as the key transcription factor responsible for the enhanced bone matrix deposition observed on hyaluronic acid, heparin and chondroitin-6-sulphate. Hyaluronic acid provided the most favourable condition for osteoblast differentiation and bone matrix synthesis. Our results confirm and emphasise the significant role of extracellular matrix in regulating cell differentiation. To summarise, glycosaminoglycans of extracellular matrix played a significant role in regulating osteoblast differenti- ation and could be exploited in the biomimetic approach of fabricating or functionalizing scaffolds for stem cell based bone tissue engineering. Copyright © 2012 John Wiley & Sons, Ltd. Received 13 June 2011; Revised 9 December 2011; Accepted 1 February 2012 Keywords extracellular matrix; mesenchymal stem cells; osteoblast differentiation; hyaluronic acid; glycosaminoglycans; osterix; bone tissue engineering; chondroitin sulphate 1. Introduction The application of tissue engineering for developing a functional tissue construct for bone regeneration requires an osteogenic cell source, an osteoconductive biomaterial scaffold and osteoinductive growth factors (Rose and Oreffo, 2002). With the discovery of mesenchymal stem cells having self-renewing capabilities and multi-lineage differentiation potential (Kolf et al., 2007), current re- search is focused on fabricating a suitable biomaterial scaffold that will support and direct these cells to the osteoblast lineage. Since scaffolds are considered the replacement of the in vivo extracellular matrix (ECM) of cells, studies are now focussing on mimicking the structural and functional aspects of this natural micro environment for developing a functional scaffold for bone tissue engineering (Smith and Ma, 2011; Lu et al., 2011; Chen et al., 2011). To achieve this goal, it is imperative to understand the regulatory role of the natural *Correspondence to: Satish Totey, Kasiak Research Pvt Ltd, 31, Makers Chamber VI, Nariman Point, Mumbai-400021, India. E-mail: smtotey@gmail.com Copyright © 2012 John Wiley & Sons, Ltd. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE RESEARCH ARTICLE J Tissue Eng Regen Med (2012) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/term.1507