Cyclic ADP-Ribose-Mediated Expansion and Stimulation of Human Mesenchymal Stem Cells by the Plant Hormone Abscisic Acid
Article first published online: 7 AUG 2008
Copyright © 2008 AlphaMed Press
Volume 26, Issue 11, pages 2855–2864, November 2008
How to Cite
Scarfì, S., Ferraris, C., Fruscione, F., Fresia, C., Guida, L., Bruzzone, S., Usai, C., Parodi, A., Millo, E., Salis, A., Burastero, G., De Flora, A. and Zocchi, E. (2008), Cyclic ADP-Ribose-Mediated Expansion and Stimulation of Human Mesenchymal Stem Cells by the Plant Hormone Abscisic Acid. STEM CELLS, 26: 2855–2864. doi: 10.1634/stemcells.2008-0488
- Issue published online: 9 JAN 2009
- Article first published online: 7 AUG 2008
- Manuscript Accepted: 22 JUL 2008
- Manuscript Received: 22 MAY 2008
- Mesenchymal stem cells;
- Cyclic ADP-ribose;
- Intracellular calcium;
- Abscisic acid
Abscisic acid (ABA) is a phytohormone involved in fundamental processes in higher plants. Endogenous ABA biosynthesis occurs also in lower Metazoa, in which ABA regulates several physiological functions by activating ADP-ribosyl cyclase (ADPRC) and causing overproduction of the Ca2+-mobilizing second messenger cyclic ADP-ribose (cADPR), thereby enhancing intracellular Ca2+ concentration ([Ca2+]i). Recently, production and release of ABA have been demonstrated to take place also in human granulocytes, where ABA behaves as a proinflammatory hormone through the same cADPR/[Ca2+]i signaling pathway described in plants and in lower Metazoa. On the basis of the fact that human mesenchymal stem cells (MSC) express ADPRC activity, we investigated the effects of ABA and of its second messenger, cADPR, on purified human MSC. Both ABA and cADPR stimulate the in vitro expansion of MSC without affecting differentiation. The underlying mechanism involves a signaling cascade triggered by ABA binding to a plasma membrane receptor and consequent cyclic AMP-mediated activation of ADPRC and of the cADPR/[Ca2+]i system. Moreover, ABA stimulates the following functional activities of MSC: cyclooxygenase 2-catalyzed production of prostaglandin E2 (PGE2), release of several cytokines known to mediate the trophic and immunomodulatory properties of MSC, and chemokinesis. Remarkably, ABA proved to be produced and released by MSC stimulated by specific growth factors (e.g., bone morphogenetic protein-7), by inflammatory cytokines, and by lymphocyte-conditioned medium. These data demonstrate that ABA is an autocrine stimulator of MSC function and suggest that it may participate in the paracrine signaling among MSC, inflammatory/immune cells, and hemopoietic progenitors.
Disclosure of potential conflicts of interest is found at the end of this article.