Sphingosine 1-Phosphate Induces Differentiation of Mesoangioblasts towards Smooth Muscle. A Role for GATA6

Abstract

Different cells can contribute to repair following vascular injury by differentiating into smooth muscle (SM) cells; however the extracellular signals involved are presently poorly characterized. Mesoangioblasts are progenitor cells capable of differentiating into various mesoderm cell types including SM cells. In this study the biological action exerted by the pleiotropic sphingolipid sphingosine 1-phosphate (S1P) in human mesoangioblasts has been initially investigated by cDNA microarray analysis. Obtained data confirmed the anti-apoptotic action of this sphingolipid and identified for the first time a strong differentiating action toward SM cells. Quantitative mRNA and protein analysis corroborated the microarray results demonstrating enhanced expression of myogenic marker proteins and regulation of the expression of transcription factor GATA6 and its co-regulator, LMCD1. Importantly, GATA6 up-regulation induced by S1P was responsible for the enhanced expression of SM-specific contractile proteins. Moreover, by specific gene silencing experiments GATA6 was critical in the pro-differentiating activity of the cytokine TGFβ. Finally, the pharmacological inhibition of endogenous S1P formation in response to TGFβ abrogated GATA6 up-regulation, supporting the view that the S1P pathway plays a physiological role in mediating the pro-myogenic effect of TGFβ. This study individuates GATA6 as novel player in the complex transcriptional regulation of mesoangioblast differentiation into SM cells and highlights a role for S1P to favour vascular regeneration.

Endothelial sphingosine kinase/SPNS2 axis is critical for vessel-like formation by human mesoangioblasts

“…Moreover, the CM harvested from H-MVEC, where SK activity was blocked or the enzyme expression levels were down-regulated, exerted a significantly diminished effect on MAB morphogenesis and migration. Previous studies have established that S1P plays a crucial role in MAB [11,24,34]; these data shed new light on the relevance of S1P signaling in the biology of MAB demonstrating that S1P released from endothelium has a prominent role on the ability of MAB to migrate and stabilize new vessels. Indeed, this sphingolipid was shown to act as a potent mitogen and an anti-apoptotic agent both in murine and human MAB [24].…”

“…Indeed, this sphingolipid was shown to act as a potent mitogen and an anti-apoptotic agent both in murine and human MAB [24]. Moreover, S1P has been demonstrated to induce differentiation of human MAB towards smooth muscle cells by transcriptional up-regulation of the transcription factors GATA6 and LMCD1 [11]. The important role of S1P in these cells is further supported by the involvement of the regulation of SK/S1P axis in the TGFβ-induced survival and smooth muscle differentiation of MAB [11,34].…”

“…Moreover, S1P has been demonstrated to induce differentiation of human MAB towards smooth muscle cells by transcriptional up-regulation of the transcription factors GATA6 and LMCD1 [11]. The important role of S1P in these cells is further supported by the involvement of the regulation of SK/S1P axis in the TGFβ-induced survival and smooth muscle differentiation of MAB [11,34]. Here, we demonstrated that both SK1 and SK2 expressed by H-MVEC have a critical role in capillary morphogenesis of MAB cultured together with H-MVEC in Matrigel.…”

“…Total RNA was extracted with TriReagent and reversetranscribed by High-Capacity cDNA Reverse Transcription Kit as previously described [11]. The quantification of target gene was performed by real time PCR employing TaqMan Gene Expression Assays.…”

“…MAB have been successfully employed in cell transplantation leading to a functional recovery of skeletal muscle in dystrophic animals [9,10]. We previously demonstrated that S1P induces the differentiation of human MAB towards smooth muscle [11]. Moreover, the important morphogenic role of S1P in these cells is further supported by the finding that the transforming growth factor beta (TGFβ)-induced differentiation of MAB towards smooth muscle involves the regulation of SK/S1P axis [11].…”