Sonic hedgehog and retinoic acid synergistically promote sensory fate specification from bone marrow-derived pluripotent stem cells

Abstract

Recent studies demonstrated that stromal cells isolated from adult bone marrow have the competence of differentiating into neuronal cells in vitro and in vivo. However, the capacity of marrow stromal cells or mesenchymal stem cells (MSCs) to differentiate into diverse neuronal cell populations and the identity of molecular factors that confer marrow stromal cells with the competence of a neuronal subtype have yet to be elucidated. Here, we show that Sonic hedgehog (Shh) and retinoic acid (RA), signaling molecules secreted from tissues in the vicinity of peripheral sensory ganglia during embryogenesis, exert synergistic effects on neural-competent MSCs to express a comprehensive set of glutamatergic sensory neuron markers. Application of Shh or RA alone had little or no effect on the expression of these neuronal subtype markers. In addition, incubation of MSCs with embryonic hindbrain͞somite͞ otocyst conditioned medium or prenatal cochlea explants promoted up-regulation of additional sensory neuron markers and process outgrowth. These results identify Shh and RA as sensory competence factors for adult pluripotent cells and establish the importance of interactions between adult pluripotent cells and the host microenvironment in neuronal subtype specification.

Tlx3 exerts context-dependent transcriptional regulation and promotes neuronal differentiation from embryonic stem cells

“…If genetic manipulation to introduce Tlx3 in ES cells accompanies any risks to the human health, then we would need to identify a signaling protein that promotes Tlx3 expression. We previously demonstrated that a conditioned medium prepared from the E10 mouse hindbrain/somite/otocyst can up-regulate Ngn1, NeuroD, Brn3a, GluR4, and VGLUT2-the same set of genes upregulated in ES cell-derived neurons by Tlx3-in adult pluripotent progenitor cells after neural induction (21). Interestingly, Tlx3 expression was also induced in these neural competent progenitor cells grown in the hindbrain/somite/otocyst conditioned medium (T.K., unpublished observations).…”

Transplantation of Mouse Embryonic Stem Cells into the Cochlea of an Auditory-Neuropathy Animal Model: Effects of Timing after Injury

“…Potential cell sources for inner ear transplantation include fetal dorsal root ganglion cells (Hu et al 2004;Regala et al 2005), neural progenitor cells (Ito et al 2001;Corrales et al 2006;), stem or progenitor cells isolated from inner ear (Li et al 2003a;Doetzlhofer et al 2004;Rask-Andersen et al 2005;Zhai et al 2005), immortalized auditory neuroblast cells (Nicholl et al 2005;Liu et al 2006a, b), ESCs and their derived neuronal cells (Li et al 2003b;Hu et al 2004Hu et al , 2005Hildebrand et al 2006;Okano et al 2005;Regala et al 2005;Coleman et al 2006;Sakamoto et al 2004;Sekiya et al 2006;Corrales et al 2006), and marrow stromal cells treated with sonic hedgehog and retinoic acid (Kondo et al 2005). ESCs derived from the inner cell mass of the blastocyst are capable of undergoing an unlimited number of divisions and differentiating into cell types of all three germ layers.…”

Stem cell transplantation for auditory nerve replacement

“…This in vitro approach has also been applied to bone marrow derived stem cells. Kondo et al (2005) demonstrated sonic hedgehog and retinoic acid when in combination induced differentiation of marrow stromal cells to a neuronal phenotype with a greater than 200-fold increase in GATA3, Irx2, Sox10, calretinin and GluR4 mRNAs (all expressed during normal development in auditory nerve neurons) and Wnt 1 induced a 400-fold increase in the expression level of Brn3a, Ngn2 (neuroD) and Ngn1, which play a role in the differentiation of auditory neurons during normal development. Falk et al (2002) found that transduction of stem cells with Neurogenin 2 (Ngn2) induced over 90% towards a neuronal phenotype.…”