• BMB Reports
• /
• v.52 no.7
• /
• pp.434-438
• /
• 2019

We have previously reported the effects of 2-(trimethylammonium)ethyl (R)-3-methoxy-3-oxo-2-stearamidopropyl phosphate [(R)-TEMOSPho], a synthetic phospholipid, on megakaryocytic differentiation of myeloid leukemia cells. Here, we demonstrate that (R)-TEMOSPho enhances megakaryopoiesis and plateletogenesis from primary hematopoietic stem cells (HSCs) induced by thrombopoietin (TPO). Specifically, we demonstrate at sub-saturation levels of TPO, the addition of (R)-TEMOSPho enhances differentiation and maturation of megakaryocytes (MKs) from murine HSCs derived from fetal liver. Furthermore, we show that production of platelets with (R)-TEMOSPho in combination with TPO is also more efficient than TPO alone and that platelets generated in vitro with these two agents are as functional as those from TPO alone. TPO can thus be partly replaced by or supplemented with (R)-TEMOSPho, and this in turn implies that (R)-TEMOSPho can be useful in efficient platelet production in vitro and potentially be a valuable option in designing cell-based therapy.

• Molecules and Cells
• /
• v.37 no.8
• /
• pp.628-635
• /
• 2014

2-(Trimethylammonium) ethyl (R)-3-methoxy-3-oxo-2-stearamidopropyl phosphate [(R)-TEMOSPho], a derivative of an organic chemical identified from a natural product library, promotes highly efficient megakaryopoiesis. Here, we show that (R)-TEMOSPho blocks osteoclast maturation from progenitor cells of hematopoietic origin, as well as blocking the resorptive function of mature osteoclasts. The inhibitory effect of (R)-TEMOSPho on osteoclasts was due to a disruption of the actin cytoskeleton, resulting from impaired downstream signaling of c-Fms, a receptor for macrophage-colony stimulating factor linked to c-Cbl, phosphoinositol-3-kinase (PI3K), Vav3, and Rac1. In addition, (R)-TEMOSPho blocked inflammation-induced bone destruction by reducing the numbers of osteoclasts produced in mice. Thus, (R)-TEMOSPho may represent a promising new class of antiresorptive drugs for the treatment of bone loss associated with increased osteoclast maturation and activity.

• BMB Reports
• /
• v.48 no.12
• /
• pp.691-695
• /
• 2015

We report that phytosphingosine, a sphingolipid found in many organisms and implicated in cellular signaling, promotes megakaryocytic differentiation of myeloid leukemia cells. Specifically, phytosphingosine induced several hallmark changes associated with megakaryopoiesis from K562 and HEL cells including cell cycle arrest, cell size increase and polyploidization. We also confirmed that cell type specific markers of megakaryocytes, CD41a and CD42b are induced by phytosphingosine. Phospholipids with highly similar structures were unable to induce similar changes, indicating that the activity of phytosphingosine is highly specific. Although phytosphingosine is known to activate p38 mitogen-activated protein kinase (MAPK)-mediated apoptosis, the signaling mechanisms involved in megakaryopoiesis appear to be distinct. In sum, we present another model for dissecting molecular details of megakaryocytic differentiation which in large part remains obscure.